Arsenic-74 is used to locate brain tumors. It has a half-life of 17.5 days. 90 mg were
used in a procedure. Write an equation that can be used to determine how much of
the isotope is left after x number of half-lives.
How much would be left after 70 days?
After x half-lifes, the amount of the isotope is:
A(x*T) = 90mg*e{-x*ln(2)}
And after 70 days, there are 5.628 mg
What is the half-life?
We define the half-life as the time such that the inital amount of a given substance reduces to half of it.
If the half-life is T, the amount of the substance can be written as:
A(t) = a*e^{-λ*t}
Where λ = ln(2)/T.
and a is the initial amount.
In this case, T = 17.5 days, then:
λ = ln(2)/17.5 days = 0.0396 / day
And we also have a = 90mg
Then the exponential equation is:
A(t) = 90mg*e^{-t*0.0396 / day}
After x half-lifes, the amount of the isotope left is:
A(x*T) = 90mg*e^{-x*T*ln(2)/T} = 90mg*e^{-x*ln(2)}
And after 70 days the amount is:
A(70 days) = 90mg*e^{-70 days*0.0396 / day} = 5.628 mg
If you want to learn more about exponential decays, you can read:
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Answer:
Y=90mg(0.5)^5
1.86 after 70 days
Step-by-step explanation:
y = 7x + 20
4x - y = -11
solve by substitution
Answer:
x = - 3, y = - 1
Step-by-step explanation:
y = 7x + 20 -----> equation 1
4x - y = - 11
4x - ( 7x + 20 ) = - 11
4x - 7x - 20 = - 11
- 3x = - 11 + 20
- 3x = 9
x = 9 / - 3
x = - 3
Substitute x = - 3 in equation 1,
y = 7 ( - 3 ) + 20
= - 21 + 20
y = - 1
Hence,
x = - 3
y = - 1
Answer:
x = -3y = -1Explanation:
y = 7x + 20 __ equation 1
4x - y = -11
y = 11 + 4x __ equation 2
using substitution method,
11 + 4x = 7x + 20
4x - 7x = 20 - 11
-3x = 9
x = -3
Find y,
y = 7x + 20
y = 7(-3) + 20
y = -1
Rob goes to a store and buys a camera originally priced at $30. The store is running a discount of 18%. The sales tax rate is 7.4%. What is the final price of the camera?
pls help asap
Answer:
$26.42
Step-by-step explanation:
P = 30 * 0.82 * 1.074 = 26.42
If claire does not make any payments, how much will she owe after ten years? $12,136.67 $3,481.24 $6,090.90 $3,232.74
The interest formulas will be used to find the amount Claire owes. If the amount has a single compounding per year, simple interest is used, otherwise, compound interest is used.
Simple InterestSimple interest is used when there is a single compounding per time period.
The amount of money after t years in is modeled by:
[tex]A(t) = A(0)(1 + rt)[/tex]
In which:
A(0) is the initial amount.r is the interest rate, as a decimal.What is compound interest?The amount of money earned, in compound interest, after t years, is given by:
[tex]A(t) = P\left(1 + \frac{r}{n}\right)^{nt}[/tex]
In which:
A(t) is the amount of money after t years. P is the principal(the initial sum of money). r is the interest rate(as a decimal value). n is the number of times that interest is compounded per year. t is the time in years for which the money is invested or borrowed.More can be learned about interest at https://brainly.com/question/25781328
Answer:
a. $12,136.67
Step-by-step explanation:
x -4 ifx>4
|
Rsm question
Answer:
x>4
d'ou: x-4>4-4
x-4>0 voilà bonnne journée
Step-by-step explanation:
what is the value of 350 - 30(-14 + 3.5)
Answer:
665
Step-by-step explanation:
PLEASE MARK ME AS BRAINLIEST AND HAVE A NICE DAY :)
Answer:
665
Step-by-step explanation:
350 - 30( - 14 + 3.5) ← evaluate the parenthesis
= 350 - 30( - 10.5) ← distribute parenthesis by - 30
= 350 + 315
= 665
Four beakers contain water as shown below.
Which two beakers of water can be combined to fill one beaker to exactly 1,000 mL?
beaker B and beaker C
beaker B and beaker C
beaker A and beaker C
beaker A and beaker C
beaker A and beaker B
beaker A and beaker B
beaker A and beaker D
beaker A and beaker D
Answer:
A&C
Step-by-step explanation:
It would be A because it has 750 mL and C because it has 250mL and 750+250=1000
Also can you mark brainlyist you dont have to
Which of the following are exact numbers? Select all that apply.
The liquid has a volume of 10.41 mL
The paper has a length of 5.2 cm.
There are 30 students in the class.
There are 100 cm in 1 m.
The exact numbers listed in this problem are given by:
There are 30 students in the class.There are 100 cm in 1 m.What are exact numbers?Exact numbers are numbers that are not rounded. Volumes and lengths, for example, are usually rounded, hence they cannot be called exact.
Thus, the exact numbers listed in this problem are given by:
There are 30 students in the class.There are 100 cm in 1 m.More can be learned about exact numbers at https://brainly.com/question/14089554
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The first term in a sequence is 84. The pattern follows the rule add 24. What are the next four terms?
Answer: 108, 132, 156, and 180
Step-by-step explanation:
If you need to add 24 to the first term for the next 4 terms, you would have
84 + 24 = 108
108 + 24 = 132
132 + 24 = 156
156 + 24 = 180
So your sequence would be 108, 132, 156, and 180 for the next 4 terms.
Jennifer wants to know how many of her company’s 1,800 employees ride the bus to work. She asks every fourth employee out of 800 entering the building from the parking garage
Given triangle ABC is congruent to DEC find m
First, we know that angle B is congruent to angle E.
2x + 40 = 5x + 10
2x + 30 = 5x
30 = 3x
x = 10
Angle B and Angle E = 60 degrees
Angle C = 14 degrees
Remember that the interior angles of a triangle always add up to 180 degrees. Now that we know 2 of the 3 angles of these triangles, and because they are congruent, all that's left to do is find Angle A/D by setting up a simple equation.
60 + 14 + D = 180
74 + D = 180
D = 106
Angle D = 106 degrees
Hope this helps!
Answer:
Step-by-step explanation:
<E = <A property of congruency.
<A = 5x + 10 Comes from the fact that <A and <E are equal.
Three angles of the triangle are given. They add to 180 degrees.
2x + 40 + x + 4 + 5x + 10 = 180 Combine like terms
8x + 54 = 180 Subtract 54 from both sides.
8x + 54 - 54 = 180 - 54 Combine
8x = 126 Divide by 8
8x/8 = 126/8
x = 15.75
<B = <D Congruency and parallel lines
<D = 2x + 40 Substitute for x
<D = 2*15.75 + 40 Combine
<D = 31.5 + 40
<D = 71.5
A survey of 100 people in New York City, NY found that.
• The probability that they take the subway each day is 0.85
• The probability that they take a Taxi each day is 0.6
• The probability that take the subway and taxi each day is 0.55
If a person is selected at random, then determine the probability thay they take either the subway or a taxi each day.
Answer: 0.9
Step-by-step explanation:
[tex]\mathrm{Total \ sample \ space \ $=100$} \\\mathrm{Event \ $A = \ taking \ subway \ each \ day}$$P(A)=0.85$$Event $B=$ taking taxi $\because P(B)=0.6$$$P(A \cap B)=0.55$$[/tex]
[tex]\begin{aligned}P(A \cup B) & \Rightarrow \text { Person taking either taxi/subway } \\&=P(A)+P(B)-P(A \cap B) \\&=(0.85-0.555)+(0.6-0.55)-0.55 \\&=1.45-0.55\\&\bf{=0.9} \end{aligned}[/tex]
what's the square root of the area of a square with side 13?
Area :-
[tex]\\ \rm\rightarrowtail side^2[/tex]
[tex]\\ \rm\rightarrowtail 13^2[/tex]
[tex]\\ \rm\rightarrowtail 169[/tex]
Square root:-
√169=13Solve the system of equations by substitution. X + y = 32 y = 7x The solution of the system is (Simplify your answer. Type an ordered pair.)
if you can can you please write out the steps
[tex]\qquad\qquad\huge\underline{{\sf Answer}}♨[/tex]
Let's solve ~
The given equations are :
[tex]\qquad \sf \dashrightarrow \:x + y = 32[/tex]
and
[tex]\qquad \sf \dashrightarrow \:y = 7x[/tex]
Now, plug in the value of y from equation 2 into equation 1 to find out the value of x ~
[tex]\qquad \sf \dashrightarrow \:x + y = 32[/tex]
[tex]\qquad \sf \dashrightarrow \:x + 7x = 32[/tex]
[tex]\qquad \sf \dashrightarrow \:8x = 32[/tex]
[tex]\qquad \sf \dashrightarrow \:x = 32 \div 8[/tex]
[tex]\qquad \sf \dashrightarrow \:x = 4[/tex]
Now, plug the value of x in equation 2 to find y
[tex]\qquad \sf \dashrightarrow \:y = 7x[/tex]
[tex]\qquad \sf \dashrightarrow \:y = 7 \times 4[/tex]
[tex]\qquad \sf \dashrightarrow \:y = 28[/tex]
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A restaurant manager gives a survey to all of his customers asking them to rate the quality of the service they received. He then keeps track of how many customers return to the restaurant during the next six months. Last year, the results showed that of the customers who reported high quality service, 90% returned for additional meals. What conclusion can be drawn from this study? (6 points) Only some customers who rate their service as high quality return for additional meals. Most customers who rate their service as high quality return for additional meals. High quality services cause customers to return for additional meals. Customers who will return for additional meals report a high quality of service.
Answer: High quality services cause customers to return for additional meals.
Step-by-step explanation: The 90% crosses out the first option. Because it's 90% we don't know if all the customers reported their service. The last one just to me wouldn't make sense.
Use numerals instead of words. If necessary, use / for the fraction bar(s).
The measure of angle 0 is 7 pie/4. The measure of its reference angle Is _°, and tan 0 is _
Answer:
-1
Step-by-step explanation:
angle 0: 7pie/4
=7*180/4
=1260/4
=315
hence reference angle(0)= 315
now, tan 0 = tan315
= tan(360-45)
= -tan45
= -1
Is this a function pls someone tell me
Answer:
No, it is not a function.
Step-by-step explanation:
In a function, each element in the domain must correspond to exactly one element in the range. That is not the case here.
Simplify:
4(r + 1) + 3r
A) 4r + 4
B) 5r + 1
C) 7r + 1
D) 7r + 4
Answer:
[tex]\boxed{\sf{D. \quad 7r+4}}[/tex]Step-by-step explanation:
Use a distributive property.
Distributive property:
[tex]\Longrightarrow:\sf{A(B+C)=AB+AC}[/tex]
⇒ 4(r+1)+3r
To multiply, first expand the form.
⇒ 4*r=4r
⇒ 4*1=4
Rewrite the problem down.
⇒ 4r+4+3r
Combine like terms.
⇒ 4r+3r+4
Solve.
Add similar to elements.
Add the numbers from left to right.
⇒ 4r+3r=7r
⇒ = 7r+4
Therefore, the correct answer is D. 7r+4.I hope this helps you! Let me know if my answer is wrong or not.
HELP ASAP !
b) findthe equation of circle having (2,3) and (4,0) as the end points of the diameter
Answer:
[tex]\left( x-3\right)^{2} +\left( y-\frac{3}{2} \right)^{2} =\frac{13}{4}[/tex]
Step-by-step explanation:
Let A(2,3) and B(4,0) be the end points of the diameter
then the segment AB is the diameter of the circle
Then the center of the circle (point M) is the midpoint of segment AB
Then M( (2+4)/2 , (3+0)/2 ) then M( 3 , 3/2 )
Now let’s find the radius r of our circle :
r = AB/2
Then
[tex]r=\frac{AB}{2} =\frac{\sqrt{(0-3)^{2}+(4-2)^2} }{2} =\frac{\sqrt{13} }{2}[/tex]
Then Equation of the circle is:
[tex]\left( x-3\right)^{2} +\left( y-\frac{3}{2} \right)^{2} = \left( \frac{\sqrt{13} }{2} \right)^{2} \\\Longrightarrow \left( x-3\right)^{2} +\left( y-\frac{3}{2} \right)^{2} =\frac{13}{4}[/tex]
PLEASE HELP ASAP
10. Mike and Pete together have $84.00. If Mike has $24.00,
what is the ratio of Pete's amount to Mike's amount?
Answer:
2.5
Step-by-step explanation:
Let M and P stand for the money that Mike(M) and Pete(P) have.
We discover that M + P = $84.00
We also find that M = $24.00
This means that :
M + P = $84.00
$24.00 + P = $84.00
P = $60.00
The ratio of P to M is ($60.00/$24.00) or 2.5 (P/M - 2.5)
George and Sarah were building a cone-shaped sand castle. after some time, the diameter of the sand shaped cone was 12 in. and the height was 14 in. what is the approximate volume of the sand cone rounded to the nearest hundreth? (show your work. remember you can draw a picture to help you solve the problem). label your answers with the correct units. use 3.14 to approximate pi answer:
they kept adding sand, and ten minutes later the volume of the sand cone had increased by 30%. what is the approximate volume of the sand cone now? label your answers with the correct units. (show your work) use 3.14 to approximate pi answer:
Answer:
why you delete my answer before question
What is 7/15+13/19+5/12 expressed as a fraction in lower terms
Which property can be used to solve the equation?
5 d = 75
addition property of equality
subtraction property of equality
multiplication property of equality
division property of equality
Answer: Division Property of equality
Step-by-step explanation:
5d= 75
1. Isolate the variable and remember, if the number is next to the letter, it means to multiply.
2. Reverse PEMDAS so instead of multiplying, divide instead.
3. 75/ 5 equals 15.
d=15
Answer: d=. 15
Step-by-step explanation:
State if each is a right triangle?
Answer:
yes
Step-by-step explanation:
because the hypotenus is the longest of all the other sizes
The roots of the equation f(x) = 0 are 1 and -2. The roots of f(2x) = 0) are - - (A) 1 and -2 (B) and - 1 (C) and 1 2 2 (D) 2 and -4 (E) -2 and 4
Answer: B
Step-by-step explanation:
When f(x) turns into f(2x), we need to halve the value of x.
The roots of f(2x) will be equal to ( 1 / 2 ) and -1.
What is a quadratic equation?It is a polynomial with a degree of 2 or the maximum power of the variable is 2 in quadratic equations. It has two solutions as its maximum power is 2.
Given that the root of function f(x) are 1 and -2. The roots of F(2x) will be calculated as:-
( x - 1 ) ( x + 2 ) =0
( 2x - 1 )( 2x + 2 ) =0
x = 1 / 2
x = -1
Therefore, the roots of f(2x) will be equal to ( 1 / 2 ) and -1.
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A pair of fair dice is cast. What is the probabiliy that one of the numbers falling uppermost is a 5, given that the two numbers falling uppermost are different?.
Using it's concept, it is found that there is a 0.3333 = 33.33% probability that one of the numbers falling uppermost is a 5.
What is a probability?A probability is given by the number of desired outcomes divided by the number of total outcomes.
The outcomes are given as follows:
(1,1), (1,2), (1,3), (1,4), (1,5), (1,6)
(2,1), (2,2), (2,3), (2,4), (2,5), (2,6)
(3,1), (3,2), (3,3), (3,4), (3,5), (3,6)
(4,1), (4,2), (4,3), (4,4), (4,5), (4,6)
(5,1), (5,2), (5,3), (5,4), (5,5), (5,6)
(6,1), (6,2), (6,3), (6,4), (6,5), (6,6)
From the list, we have that:
There are 30 outcomes in which the numbers are different.In those, there are 10 in which one 5 appears.Hence, the probability is given by:
p = 10/30 = 0.3333 = 33.33%.
More can be learned about probabilities at https://brainly.com/question/14398287
What percentage of Africa is savanna?
less than ten percent
approximately twenty-five percent
almost fifty percent
close to seventy percent
Answer:
C, Almost fifty percent
Step-by-step explanation: I just got it right.
FIRST ANSWER GETS CROWN!
Answer:
7 is first
2 is second
7.3 is third
Step-by-step explanation:
Answer:
see explanation
Step-by-step explanation:
the horizontal leg = 7 units
the vertical leg = 2
using Pythagoras' identity to find the distance d
d = [tex]\sqrt{7^2+2^2}[/tex] = [tex]\sqrt{49+4}[/tex] = [tex]\sqrt{53}[/tex] ≈ 7.3 ( to 1 dec. place )
1/(√2+√3)-√4 pls explain i dont understand
Hey there!
1/(√2+√3)-√4
=−2−√2+√3
(Decimal: -1.682163)
NEED HELP ASAP!!!! GIVING BRAINLIEST+ 30 POINTS TO WHOEVER CAN ANSWER THESE TWO QUESTIONS THE BEST!!!