Answers
Answer:
-14/2 , 1/3 and 0.325 are the rational numbers
Related Questions
The formula for the surface area of a cylinder is:
SA = 2π r 2 + 2πrh note: that π= 3.14
a. Solve for h showing all work.
b. If the height of a can of soup is 5 inches and the radius is 1.5 inches, what is the surface area?
Answers
Answer:
Below in bold.
Step-by-step explanation:
a. SA = 2π r^2 + 2πrh
2πrh = SA - 2π r^2
h = (SA - 2πr^2)/2πr
When π = 3.14 we have
h = (SA - 6.28r^2)/ 6.28r
b. SA = 6.28*1.5^2 + 6.28*1.5* 5
= 61.23 in^2
In a bag of mini candy bars, 40% of the candy bars are Snickers. There are 120 Snickers in the bag. How many total mini candy bars are in the bag?
Answers
Answer:
The amswer is 48.
Step-by-step explanation:
120×0.40=48
4(x+9)=2x-6
Solve for x
Answers
Answer:
-21
Step-by-step explanation:
4(x+9) = 4x+36
4x+36 = 2x-6
-36 -36
minus 36 from both sides
4x = 2x-42
2x = -42
-42/2 = -21
x = -21
Hi there!
We are given the equation below:
[tex] \large \boxed{4(x + 9) = 2x - 6}[/tex]
1. Expand 4 in the expression.
When expand in the expression, it is like multiply everything in the expression. So when we expand 4 in x+9, it becomes 4(x)+9(4).[tex] \large{(4 \times x) + (9 \times 4) = 2x - 6} \\ \large{(4x) + (36) = 2x - 6}[/tex]
Cancel the brackets.
[tex] \large{4x + 36 = 2x - 6}[/tex]
2. Isolate x-term and solve for the variable.
Think it easy. If you want to isolate x-term then what should you do? Well simply swap sides, and change the operator/sign.[tex] \large{4x - 2x = - 6 - 36}[/tex]
Finally, combine like terms.
[tex] \large{2x = - 42}[/tex]
Then divide both sides by 2 so we can finally leave only x-term.
[tex] \large{ \frac{2x}{2} = \frac{ - 42}{2} } \\ \large \boxed{x = - 21}[/tex]
3. Check the solution if it is right or wrong.
This step is optional but if you are not confident on your answer, this step is recommended.To check the answer, we simply substitute the value of x which is -21 in the equation and see if both sides are equal or not. If both sides are equal then the answer is correct, if not then the answer is wrong. Therefore,
[tex] \large{4(x + 9) = 2x - 6 \longrightarrow 4( - 21 + 9) = 2 ( - 21) - 6} \\ \large{4( - 12) = - 42 - 6} \\ \large{ - 48 = - 48}[/tex]
Since both sides are equal when substitute in x = -21.
4. Answer
Hence, the answer for this equation is x = -21.I hope this helps and let me know if you have any doubts!
the radius of a circle in cm ,with area 77 over 2 cm square is
Answers
Answer:
7/√2 cm
Step-by-step explanation:
Area of circle = 77 cm^2
=> π(r)^2 = 77
=> (22/7) x (r)^2 = 77
=> (r)^2 = (77 x 7) / 22
=> (r)^2 = 49/2
=> (r) = 7/√2 cm
Assume that a randomly selected subject is given a bone density test. Those test scores are normally distributed with a mean of 0 and a standard deviation of 1. Find the probability that a given score is less than and draw a sketch of the region.
Answers
Answer:
0.5000
Step-by-step explanation:
According To The Question,
The Area under the Standard Normal Curve, We Can Use the Statistical Tables , That Reported Area As P(z < a) .
Thus, We need to use the following Relationship.
P(z > a) = 1 - P(z < a)Now solve, P(z > 0) = 1 - P(z < 0) ⇔ 1 - 0.5000 ⇔ 0.5000
(Diagram, Please Find in Attachment)
Find the measure of the are or central angle indicated. Assume that lines which appear to be
diameters are actual diameters.
2) m SPU
Answers
Answer:
120°
Step-by-step explanation:
m L SPU = 180° - 60° = 120°
In communicating with an orbiting satellite, suppose that a 30-bit message is sent to thesatellite. Transmission of messages can sometimes be distorted. If the probability of eachbit being received incorrectly is 0.001, where each bit is received independently of the others,what is the probability that at least one bit is received incorrectly?
Answers
Answer:
0.0296 = 2.96% probability that at least one bit is received incorrectly.
Step-by-step explanation:
For each bit, there are only two possible outcomes. Either it is received correctly, or it its not. Each bit is received independently of the others, which means that the binomial probability distribution is used to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
The probability of each bit being received incorrectly is 0.001
This means that [tex]p = 0.001[/tex]
30-bit message
This means that [tex]n = 30[/tex]
What is the probability that at least one bit is received incorrectly?
This is:
[tex]P(X \geq 1) = 1 - P(X = 0)[/tex]
In which
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 0) = C_{30,0}.(0.001)^{0}.(0.999)^{30} = 0.9704[/tex]
Then
[tex]P(X \geq 1) = 1 - P(X = 0) = 1 - 0.9704 = 0.0296[/tex]
0.0296 = 2.96% probability that at least one bit is received incorrectly.
If a product normal retails for $40, and a customer has a coupon for 15% off, what will the discounted price of the product be?
Answers
Answer:
$34
Step-by-step explanation:
price of the product = $40
coupon = 15% off
discount price = 15% of price of a product
=15/100 * $40
=$600/100
=$6
New price of the product = original price - discount
=$40 - $6
=$34
What is cos 0 when sin 0= 2/3
Answers
Answer:
your answer is √7/3
Step-by-step explanation:
your answer is √7/3
Suppose your marketing colleague used a known population mean and standard deviation to compute the standard error as 67.5 for samples of a particular size. You don't know the particular sample size but your colleague told you that the sample size is greater than 70. Your boss asks what the standard error would be if you quadruple (4x) the sample size. What is the standard error for the new sample size
Answers
Answer:
The standard error for the new sample size will be of 33.75.
Step-by-step explanation:
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
Standard error as 67.5 for samples of a particular size.
We have that [tex]s = \frac{\sigma}{\sqrt{n}}[/tex], that is, the standard error is inversely proportional to the square root of the sample size, so if you quadruple (4x) the sample size, the standard error will be divided by half. So
67.5/2 = 33.75
The standard error for the new sample size will be of 33.75.
Which type of parent function is f(x) =1/2
Answers
Answer:
I think you are missing something unless the answer is a horizontal line.
Step-by-step explanation:
Answer:
square root
Step-by-step explanation:
just took the test :)
Consider the following conditional statement. Determine the contrapositive
of the statement and then determine if the contrapositive is true or false.
If two angles are not complements, then their measures do not add up to 180°.
The contrapositive of the statement is true.
The contrapositve of the statement is false.
Answers
Answer:
The contrapositive of the statement is true.
Step-by-step explanation:
For a general statement:
p ⇒ q
The contrapositive statement is:
¬q ⇒ ¬p
where:
¬q is the negation of the proposition q.
Here we have the statement:
If two angles are not complements, then their measures do not add up to 180°
So we have:
p = two angles are not complements
q = their measures do not add up to 180°
Then the negations are:
¬p = two angles are complements
¬q = their measures do add up to 180°
The contrapositive statement is:
"if for two angles their measures do add up to 180°, then the two angles are complements"
This is true, if for two angles the sum of their measures is equal to 180°, then these angles are complementary.
Then: The contrapositive of the statement is true.
cos(x+pi/3)-sin2x=0 ahihihihihihiihihihihihih
Answers
Answer:cos(x+pi/3) - sin2x=0
<=> cos(x+pi/3)=sin2x
<=> cos(x+pi/3)=cos(pi/2-2x)
<=>x+pi/3=pi/2-2x+k2pi
Or x+pi/3=-pi/2 +2x+k2pi
<=>x=pi/18 + k2pi/3
Or x=5pi/6 +k2pi
Step-by-step explanation:
The population of a certain town was 10,000 in 1990. The rate of change of the population, measured in people per year, is modeled by , where t is measured in years since 1990. Discuss the meaning of . Calculate the change in population between 1995 and 2000. Do we have enough information to calculate the population in 2020
Answers
The question is incomplete. The complete question is :
The population of a certain town was 10,000 in 1990. The rate of change of a population, measured in hundreds of people per year, is modeled by P prime of t equals two-hundred times e to the 0.02t power, where t is measured in years since 1990. Discuss the meaning of the integral from zero to twenty of P prime of t, d t. Calculate the change in population between 1995 and 2000. Do we have enough information to calculate the population in 2020? If so, what is the population in 2020?
Solution :
According to the question,
The rate of change of population is given as :
[tex]$\frac{dP(t)}{dt}=200e^{0.02t}$[/tex] in 1990.
Now integrating,
[tex]$\int_0^{20}\frac{dP(t)}{dt}dt=\int_0^{20}200e^{0.02t} \ dt$[/tex]
[tex]$=\frac{200}{0.02}\left[e^{0.02(20)}-1\right]$[/tex]
[tex]$=10,000[e^{0.4}-1]$[/tex]
[tex]$=10,000[0.49]$[/tex]
=4900
[tex]$\frac{dP(t)}{dt}=200e^{0.02t}$[/tex]
[tex]$\int1.dP(t)=200e^{0.02t}dt$[/tex]
[tex]$P=\frac{200}{0.02}e^{0.02t}$[/tex]
[tex]$P=10,000e^{0.02t}$[/tex]
[tex]$P=P_0e^{kt}$[/tex]
This is initial population.
k is change in population.
So in 1995,
[tex]$P=P_0e^{kt}$[/tex]
[tex]$=10,000e^{0.02(5)}$[/tex]
[tex]$=11051$[/tex]
In 2000,
[tex]$P=10,000e^{0.02(10)}$[/tex]
[tex]=12,214[/tex]
Therefore, the change in the population between 1995 and 2000 = 1,163.
In a mathematics each correct answer gains 5 marks - However, 1 mark is deducted for each incorrect answer. Mary answered 30 questions for a total of 78 marks Determine the number of correct and incorrect questions Mary answered.
Answers
Answer:
Correct answers= 18
Incorrect answers=30-18= 12 answers
Step-by-step explanation:
total questions=30
correct answers= x
incorrect answers= 30-x
given: 5 marks for each correct answer
therefore, marks for correct answers = 5*x = 5x
Given: 1 mark deducted for every incorrect answer
therefore, marks deducted = 1(30-x) = 30-x
Total marks scored= 78
★ The Difference of Marks scored for Correct Answers and Marks deducted for Incorrect Answers should be equal to 78
5x- (30-x) =78
5x-30+x=78
5x+x=78+30
6x= 108
x=108/6 = 18
Correct answers= 18
Incorrect answers=30-18= 12 answers
16. Using divisibility tests, check whether the number 240720 is divisible by
2, 3, 4, 5, 6, 8, 9, 10 and 11. (Give reason)
Answers
3: it is, because the sum of the digit, 2+4+7+2=15, is divisible by 3
4. it is, because the last 2 digits, 20, is divisible by 4
5. it is, because last digit is 0
6. it is, because it is divisible by 2 and 3
8. it is, because the last 3 digits, 720, is divisible by 8
9. It is not, because the sum of the digits, which is 15, is not divisible by 9
10. It is, because the last digit is 0
11. It is not, because the difference of alternating digits, which is 2+0+2-4-7-0, is not divisible by 11
if (x) - **4, g(x) = x= 2, and h(x) = 4x+1, what is (f• Hºg)(x)?
2x+16
o (fe hºg)(x) =
2x+4
o (fonog)(x)=
4x-3
o (f• hºg)(x)- Ax=1
4x-5
o (f• nºg)(x) = AX-
Answers
Answer:
c
Step-by-step explanation:
11 Roger has m toy cars. Don has twice as many cars as Roger. Larry has five more cars than Roger. Write down an expression, in terms of m, to complete each statement. Don has cars H Larry has cars
Answers
Step-by-step explanation:
Roger has m toy cars.→ Number of cars Roger has = m
Don has twice as many cars as Roger.→ Number of cars Don has = 2(Cars Roger has)
→ Number of cars Don has = 2m
Larry has five more cars than Roger.→ Number of cars Larry has = 5 + (Cars Roger has)
→ Number of cars Larry has = 5 + m
Please help ASAP ASAP
Answers
Step-by-step explanation:
[tex] \sqrt{53} [/tex]
Choose the system for the graph.
Answers
========================================================
Explanation:
The darkest shaded region is in the northern most region. This region is above both blue boundary lines.
A sample point from this region is (5,2)
We'll plug these coordinates into the first inequality of choice A
[tex]3x+4y \le 12\\\\3(5)+4(2) \le 12\\\\23 \le 12\\\\[/tex]
which is false. So we can rule out choice A.
We can rule out choice B for the exact same reason.
The answer is between C and D
---------------------------
Let's plug those x,y coordinates into the first inequality of choice C
[tex]3x+4y \ge 12\\\\3(5)+4(2) \ge 12\\\\23 \ge 12\\\\[/tex]
which is true. So far, so good.
Now repeat for the second inequality of choice C
[tex]2x-5y \ge 10\\\\2(5)-5(2) \ge 10\\\\0 \ge 10\\\\[/tex]
which is false. We rule out choice C. Choice D is the only thing left, so it must be the answer.
---------------------------
Let's check the second inequality of choice D just for the sake of completeness
[tex]2x-5y \le 10\\\\2(5)-5(2) \le 10\\\\0 \le 10\\\\[/tex]
which is true.
We can see that (x,y) = (5,2) makes both inequalities of choice D to be true, and therefore we have found the final answer.
Answer: TRUST ITS THE CHOICE D
Step-by-step explanation:
3
2+
LAN
1
As
→
-4
-3
-2
-1
1
2
3
4
-1-
MY
-2
Col
-3-
SA
MY
What is the slope of the line?
Pro
Answers
Answer:
1/2
Step-by-step explanation:
choose 2 points, I chose (-3,2) (1,4)
[tex]m = \frac{4 - 2}{1 - ( - 3)} = \frac{2}{4} = \frac{1}{2} [/tex]
Represent the following sentence as an algebraic expression, where "a number" is the letter x.
\text{7 is added to a number.}
7 is added to a number.
Answers
Answer:
7+x
Step-by-step explanation:
X will be the unknown
what is the average rate of change from 0 to 2 of the function represented by the graph? Enter your answer, as a simplified fraction, in the box
Answers
Answer:
=>The graph of an exponential relation is also non-linear.
=>The graph of an exponential relation becomes nearly parallel to x-axis on one and then curves upward and becomes nearly parallel to the y-axis on the other sid.
The average rate of change from 0 to 2 of the function represented by the graph is [tex]\frac{3}{2}[/tex].
What is average rate of change?It is a measure of how much the function changed per unit, on average, over that interval. It is derived from the slope of the straight line connecting the interval's endpoints on the function's graph.
According to the question
[tex]x_{1} =0[/tex], [tex]x_{2} =2[/tex]
f(0) = 1, f(2) = 4
The average rate of change = [tex]\frac{f(x_{2})-f(x_{1}) }{x_{2}-x_{1} }[/tex]
= [tex]\frac{f(2)-f(0) }{2-0 }[/tex]
= [tex]\frac{4-1}{2}[/tex]
= [tex]\frac{3}{2}[/tex]
Hence, the average rate of change from 0 to 2 of the function represented by the graph is [tex]\frac{3}{2}[/tex].
Find out more information about average rate of change here
https://brainly.com/question/13235160
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los tornillos vienen en bolsa de 100. cada 10 bolsas se empaqueta una caja. las cajas se embalan de a 10 en cajones y los cajones se guardan de a 10 en un contenedor para ser transportados. ¿ cuantos tornillos lleva un contenedor?
Answers
Answer:
lleva 10 000 tornillos un contenedor
Step-by-step explanation:
Consider the following system of equations:
y = −2x + 3
y = x − 5
Which description best describes the solution to the system of equations?
Lines y = −2x + 3 and y = 3x – 5 intersect the x-axis.
Line y = −2x + 3 intersects line y = x − 5.
Lines y = −2x + 3 and y = 3x − 5 intersect the y-axis.
Line y = −2x + 3 intersects the origin.
Answers
Hi there!
»»————- ★ ————-««
I believe your answer is:
"Line y = −2x + 3 intersects line y = x − 5."
»»————- ★ ————-««
Here’s why:
When the system of equations are graphed, they would intersect at a point. This means that there is a solution to the system. The solution is [tex](\frac{8}{3} ,-\frac{7}{3} )[/tex].While the statement that the lines intersect the x-axis is true, the question asks the statement that describes the solution. The solution is the point of intersection between the two lines.⸻⸻⸻⸻
See the Graph Attached
⸻⸻⸻⸻
»»————- ★ ————-««
Hope this helps you. I apologize if it’s incorrect.
By how much is the sum of 3 2/3 and 2 1/5 less than 7
Answers
Step-by-step explanation:
32/3+21/5÷7
14.87÷7
2.124
No step by steps or links please
Answers
Answer:
Six at top, ten at second, twenty-seven at third, and four at bottom.
PLEASE HELP ME ASAP! ILL GIVE YOU ALL OF MY POINTS PLEASE HELP.
A large container of breath mints has a mass of 50 g. A small container has a mass of 10 g. What is the percent decrease from the mass of the large container to the mass of the small container? Show your work.
Answers
Answer:
80 percent decrease
Step-by-step explanation:
80% of 50 = 40 and 50 - 40 = 10
Answer:
It decreases 80%
Step-by-step explanation:
If the 50g one is 100%, and the 10g one is a fraction of that, find out what 10/50 is as a percent.
10/50= 20%
Because this is the remaining mass, the other 80% has been deducted meaning that the mass of the large container has decreased 80% to get to the mass of the smaller one.
A pizza company runs a marketing campaign based on their delivery time for pizzas. They claim that they will deliver a pizza within 30 minutes of ordering or it is free. In practice the time it takes to prepare a pizza and it being delivered is normally distributed with mean 25 minutes and standard deviation 3 minutes. What is the probability a pizza is delivered for free?On a particular Sunday, 40 pizzas were ordered. What is the probability that more than 2 were delivered for free?If the company wants to reduce the proportion of pizzas that are delivered free to 1%, what should the delivery time be advertised as?
Answers
Answer:
0.0475 = 4.75% probability a pizza is delivered for free.
0.2955 = 29.55% probability that more than 2 were delivered for free.
The delivery time should be advertised as 32 minutes.
Step-by-step explanation:
To solve this question, we need to understand the binomial distribution and the normal distribution.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Normally distributed with mean 25 minutes and standard deviation 3 minutes.
This means that [tex]\mu = 25, \sigma = 3[/tex]
What is the probability a pizza is delivered for free?
More than 30 minutes, which is 1 subtracted by the p-value of Z when X = 30.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{30 - 25}{3}[/tex]
[tex]Z = 1.67[/tex]
[tex]Z = 1.67[/tex] has a p-value of 0.9525
1 - 0.9525 = 0.0475
0.0475 = 4.75% probability a pizza is delivered for free
What is the probability that more than 2 were delivered for free?
Multiple pizzas, so the binomial probability distribution is used.
0.0475 probability a pizza is delivered for free, which means that [tex]p = 0.0475[/tex]
40 pizzas, which means that [tex]n = 40[/tex]
This probability is:
[tex]P(X > 2) = 1 - P(X \leq 2)[/tex]
In which
[tex]P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2)[/tex]
So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 0) = C_{40,0}.(0.0475)^{0}.(0.9525)^{40} = 0.1428[/tex]
[tex]P(X = 1) = C_{40,1}.(0.0475)^{1}.(0.9525)^{39} = 0.2848[/tex]
[tex]P(X = 2) = C_{40,2}.(0.0475)^{2}.(0.9525)^{38} = 0.2769[/tex]
Then
[tex]P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2) = 0.1428 + 0.2848 + 0.2769 = 0.7045[/tex]
[tex]P(X > 2) = 1 - P(X \leq 2) = 1 - 0.7045 = 0.2955[/tex]
0.2955 = 29.55% probability that more than 2 were delivered for free.
If the company wants to reduce the proportion of pizzas that are delivered free to 1%, what should the delivery time be advertised as?
The 99th percentile, which is X when Z has a p-value of 0.99, so X when Z = 2.327.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]2.327 = \frac{X - 25}{3}[/tex]
[tex]X - 25 = 2.327*3[/tex]
[tex]X = 32[/tex]
The delivery time should be advertised as 32 minutes.
Let r be the binomial random variable corresponding to the number of people that will live beyond their 90th birthday,
r ≥ 15.
We want to find
P(r ≥ 15)
using the normal approximation given 625 trials and a probability of a 4.4% success on a single trial.
Answers
Answer:
P(r ≥ 15) = 0.9943.
Step-by-step explanation:
We use the normal approximation to the binomial to solve this question.
Binomial probability distribution
Probability of exactly x successes on n repeated trials, with p probability.
Can be approximated to a normal distribution, using the expected value and the standard deviation.
The expected value of the binomial distribution is:
[tex]E(X) = np[/tex]
The standard deviation of the binomial distribution is:
[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]
Normal probability distribution
Problems of normally distributed distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
When we are approximating a binomial distribution to a normal one, we have that [tex]\mu = E(X)[/tex], [tex]\sigma = \sqrt{V(X)}[/tex].
625 trials and a probability of a 4.4% success on a single trial.
This means that [tex]n = 625, p = 0.044[/tex]
Mean and standard deviation:
[tex]mu = E(X) = np = 625*0.044 = 27.5[/tex]
[tex]\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{625*0.044*0.956} = 5.13[/tex]
P(r ≥ 15)
Using continuity correction, this is [tex]P(r \geq 15 - 0.5) = P(r \geq 14.5)[/tex], which is 1 subtracted by the p-value of Z when X = 14.5. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{14.5 - 27.5}{5.13}[/tex]
[tex]Z = -2.53[/tex]
[tex]Z = -2.53[/tex] has a p-value of 0.0057
1 - 0.0057 = 0.9943
So
P(r ≥ 15) = 0.9943.