A 15-g sample of radioactive iodine decays in such a way that the mass remaining after t days is given by
m(t) = 15e−0.073t,
where
m(t)
is measured in grams. After how many days is there only 5 g remaining?

Answers

Answer 1

15 days

Step-by-step explanation:

The half-life equation is given as

[tex]m(t) = m(0)e^{-0.073t}[/tex] (1)

where m(0) is the initial mass of radioactive iodine at t = 0. To solve for the time t, let's put the exponential part on the left-hand side:

[tex]e^{-0.073t} = \dfrac{m(t)}{m(0)}[/tex]

Taking the natural logarithm of both sides to get

[tex]\ln{e^{-0.073t}} = \ln\left[\dfrac{m(t)}{m(0)}\right][/tex] (2)

Recall the following properties of logarithms:

[tex]\ln{A}^b = b\ln{A}[/tex]

[tex]\ln{e} = 1[/tex]

We can rewrite Eqn(2) as

[tex]-0.073t = \ln\left[\dfrac{m(t)}{m(0)}\right][/tex]

Solving for t, we get

[tex]t = -\dfrac{1}{0.073}\ln\left[\dfrac{m(t)}{m(0)}\right][/tex]

Since m(0) = 15 gm and m(t) = 5 gm, then the amount of time that elapses to reduce the mass down to 5 gm is

[tex]t = -\dfrac{1}{0.073}\ln\left(\dfrac{5\:\text{g}}{15\:\text{g}}\right)[/tex]

[tex]\:\:\:\:\:= 15\:\text{days}[/tex]


Related Questions

Identify the given quadrilateral
Can anyone tell me if these are correct?

Answers

28 might be a parallelogram

The teacher has 10 pizzas. She can give each child 1/8 of a pizza. How many students will get a slice.

Answers

Answer:

80

Step-by-step explanation:

1 pizza has 8 [tex]\frac{1}{8}[/tex]ths. 10 pizzas have 10 × 8 = 80 1/8ths. So 80.

Answer:

80 because if one student gets 1/8 that means 8 students get one slice out of the pizza multiply 8 by 10 and it equals 80

The product of two consecutive even integers is 6 more than 3 times their sum. The integers are: a. 6,8 b. 16, 20 12, 16 d. 20, 24 C.​

Answers

Answer:

   a. 6,8

Step-by-step explanation:

The only offered answer choice that lists consecutive even integers is ...

   a. 6,8

_____

Consecutive even integers differ by 2, not 4.

__

Check

The product is 6×8 = 48.

Three times the sum is 3(6+8) = 3(14) = 42.

The product is 6 more than 3 times the sum. 42+6 = 48

Help me fast please worth 14

Answers

Answer:

its the last one i think

Step-by-step explanation:

.

plz help with my math plz!!!!

Answers

Step-by-step explanation:

This is an isosceles triangle because in an isosceles triangle angles opposite to each of the equal sides must also be equal. Since the diagram shows 2 equal angles we can say its isosceles.

So 3(x+2) = 24

8= x+2

x = 6

Answer:

x = 6

Step-by-step explanation:

The triangle given is an isosceles triangle.

Which means, the two sides and the two angles will be the same.

One of the sides is 24.

The other is 3 ( x + 2 )

Hence, we will get this equation.

24 = 3 ( x + 2 )

24 = 3x + 6

24 - 6 = 3x

18 = 3x

6 = x

Thus, x = 6.

I hope it helps.

Holding the price level constant, we would expect that if the multiplier is 1.5, the cumulative effect of this change in M on AD will be: $ billion

Answers

Holding the price level constant, we would expect that if the multiplier is 1.5, the cumulative effect of this change in M on AD will be: $ billion

The equilateral triangle with side 12 has altitude

Answers

Answer:

C

Step-by-step explanation:

what is the value of x

Answers

Answer:X= 41

Step-by-step explanation:

What is the answer for the following equation?

53 x 65 + 36 ÷ 5 = ?

Answers

Answer:

3452.2

Step-by-step explanation:

3452.2

Answer:

3452.2

Step-by-step explanation:

we have to use bodamas rule..

A contractor purchases 7 pairs of padded work gloves for $103.32. How much would he pay if he wanted to buy 12 pairs

Answers

103.32 : 7 = 14.76
14.76 x 12 = 177.12$

Answer:

$177.12

Step-by-step explanation:

$103.32 divided by 7 to find out how much 1 pair costs= $14.76

$14.76x12= $177.12

Bronte walks 1.5 miles on a trail. Then he jogs at a speed of 5 miles per hour. Bronte's total distance walking and jogging is 5.25 miles. How long does he jog?

Answers

Answer:

3.75 hours.

Step-by-step explanation:

5.25-1.5 = 3.75

so 3.75 hour

A

Hope this helps plz hit the crown :D

A rectangular garden is 5 ft longer than it is wide. Its area is 4550 ft. What are its dimensions?

Answers

Step-by-step explanation:

Area= lxb

L = 5+d

area= d(5+d)

4550=d²+5d

d²+5d-4550=0

d2+5d−4550=0

(d−65)(d+70)=0

d−65=0 or d+70=0

d=65 or d=−70

dimensions= 65, 70

Write an equation of the line that passes through (−2,3) and (0,8).

An equation is y=
.

Answers

Answer:

Step-by-step explanation:

y = mx + b

b is the y intercept and occurs where x = 0. One of our select points has an x value of 0, therefore b = 8

m is the slope and is found as the change in y over the change in x

m = Δy/Δx = (8 - 3) / (0 - (-2)) = 5/2

y = 5x/2 + 8

The circumference of a circle is 28.888 centimeters. What is the circle's radius?
Use 3.14 for pi

Answers

Answer:

4.6

Step-by-step explanation:

28.888 / 3.14 = 9.2

9.2 / 2 = 4.6

ANSWER USING STEPS: find the inverse function of y=-5x-7

Answers

the inverse of y is =x+7

Step-by-step explanation:

y=5x-7

then solve for x

5x=y+7

x=(y+7)/5

then exchange x with y

y=(x+7)/5

The inverse of the given function is expressed as:

-(x + 7)/5

How to find the inverse of the function?

The given function is expressed as:

y = -5x - 7

Replacing y with x and vice versa gives us:

x = -5y - 7

Add 7 to both sides gives:

x + 7 = -5y

divide both sides by -5 gives us:

-(x + 7)/5 = y

Thus, we conclude that the inverse of the given function is expressed as:

-(x + 7)/5

Read more about Inverse of Function at: https://brainly.com/question/3831584

#SPJ3

Find the area (A) of the figure below: 166) 6cm A) 18 square cm B) 35 square cm 12cm C) 72 square cm D) 144 square cm 167) 12 in A) 37.68 square inches B) 72.52 square inches C) 108.12 square inches D) 113.09 square inches​

Answers

Answer:

166) C. 72 square cm        167) D. 113.09 square inches

Step-by-step explanation:

166) Parallelogram area formula is A=Base x height

A= 6 x 12

A= 72

167) Circle area formula A=πr²

r= half of diameter (12)

A=π(6)²

A=112.09

1. Transplant operations have become routine. One common transplant operation is for kidneys. The most dangerous aspect of the procedure is the possibility that the body may reject the new organ. There are several new drugs available for such circumstances and the earlier the drug is administered, the higher the probability of averting rejection. The New England Journal of Medicine recently reported the development of a new urine test to detect early warning signs that the body is rejecting a transplanted kidney. However, like most other tests, the new test is not perfect. In fact, 20% of patients that experience kidney rejection and 9% of patients that do not experience kidney rejection receive a test result that proves to be incorrect. Physicians know that in about 30% of kidney transplants the body tries to reject the organ. If the new test has a positive result (indicating early warning of rejection), what is the probability that the body is attempting to reject the kidney?

Answers

Using conditional probability, it is found that there is a 0.7921 = 79.21% probability that the body is attempting to reject the kidney.

Conditional Probability

[tex]P(B|A) = \frac{P(A \cap B)}{P(A)}[/tex]

In which

P(B|A) is the probability of event B happening, given that A happened. [tex]P(A \cap B)[/tex] is the probability of both A and B happening. P(A) is the probability of A happening.

In this problem:

Event A: Positive test.Event B: Body attempting to reject the kidney.

The percentages associated with a positive test are:

80% of 30%(experience kidney rejection).9% of 70%(do not experience kidney rejection).

Hence:

[tex]P(A) = 0.8(0.3) + 0.09(0.7) = 0.303[/tex]

The probability of both a positive test and the body attempting to reject the kidney is:

[tex]P(A \cap B) = 0.8(0.3) = 0.24[/tex]

Hence, the conditional probability is:

[tex]P(B|A) = \frac{0.24}{0.303} = 0.7921[/tex]

0.7921 = 79.21% probability that the body is attempting to reject the kidney.

A similar problem is given at https://brainly.com/question/25553471

Need help with this geometry question

Answers

The Answer Is Number 1

Answer:

The first option:yellow shirt, white trouseryellow shirt, black trousergreen shirt, white trousergreen shirt, black trouser

Step-by-step explanation:

To find the possibilities, you would see that you would have two yellow shirts and two green shirts with different trousers, so you can eliminate the bottom two. And because there will be two of each shirt with defferent trousers, it will be the same for trousers: two of each trouser will be in the possibilities. The only one that fits this description, is the first one.

yellow shirt, white trouser

yellow shirt, black trouser

green shirt, white trouser

green shirt, black trouser

What is the value of ?
T
80°
25°
R
?
P


PLEASE

Answers

9514 1404 393

Answer:

  105°

Step-by-step explanation:

The exterior angle marked "?" is equal to the sum of the remote interior angles:

  ? = 25° +80°

  ? = 105°

If 3 horses never choose your height, can Jennifer buy 7 gallons of milk? What if Sydney gets a house in orange juice liters?
Write your answer in simplest form and interpret how and why it do no.

Answers

jennifer cannot buy seven gallons of milk as sydney is the one with the 3 horses. Sydney gets the house in orange juice liters the horses will choose her height and not jennifer’s.

16 is 80% of what number?
O A. 20
O B. 12.8
O C. 500
O D. 128

Answers

Answer:

A. 20

Step-by-step explanation:

1. To solve this problem, instead of doing 80/100 times 16, we can do 100/80 times 16 (inverse of percentage, basically).

[tex]\frac{100}{80} *16[/tex] [tex]\frac{5}{4} *16[/tex] [tex]\frac{80}{4}[/tex] [tex]20[/tex]

Therefore, the answer is A. 20.

please answer numbers 1-5 i need them soon

Answers

Answer:

Step-by-step explanation:

1) 1. AB ≅ CD                 Given

 2. AD ≅ CB                  Given

 3 . BD ≅ BD                  Reflexive property

 4. ΔABD ≅ ΔCBD         S S S congruent

2) 1. GH // JK                  Given

   2. ∠HGJ ≅∠KJG        Given

   3. GH ≅ JK                 Given

  4 . GJ ≅ GJ                    Reflexive property

   5. ΔHGJ ≅ ΔKJG         S A S congruent

3) ΔJNK ≅ ΔMNL             SSS congruent

  JK = ML                           CPCT

 JK = 160 ft

4) ΔRPS ≅ ΔTQS                A A S congruent

  RS ≅ TS

RS = 85 m

5)ΔDEF ≅ΔGHJ

 GJ  = DE       {CPCT}

6x - 13 = 3x + 2

6x = 3x + 2 + 13

6x = 3x + 15

6x - 3x = 15

3x = 15

 x = 15/3

x = 5

HJ = 5x = 5*5 = 25

7 divided by 1946
i need the anwer

Answers

Answer: 278
Explanation: Just so long division

Hi , what is sun helppp pls

Answers

Answer: sun are the main light source

Step-by-step explanation:

Answer:

What is sun ?

»The Sun is a star. It is a huge, spinning, glowing sphere of hot gas.

A 16" × 16" square tray can hold at most 9 bagels placed side by side, as shown below. At most how many bagels can a 32" × 32" square tray hold if bagels are placed side by side?\

Answers

Answer:

At most it can hold 18 bagels

Step-by-step explanation:

So we can make this an equation

16 · 16 square tray = 9 bagels on top of it

We just doubled both sides of it

giving us 32 · 32 square tray = 18 bagels can be held.

help fast
E explaination​

Answers

Answer:

a)3.4

b)8.3

c)6.30

d)19

Step-by-step explanation:

hope it can help you lovelots

#LEARN WITH BRAINLY

From 8:00 am to 8:20 am, Lisa picked 1/4 of a pound of strawberries. If she continues picking strawberries at this rate, how many pounds of strawberries will she pick in 4 hours?

Answers

Answer:

3 lbs

Step-by-step explanation:

20 mins is 1/4 lb (4oz)

1 hr is 3/4 lb (12 oz)

4 hrs= 3/4 lb or 12 oz × 4

4 hrs= 3 lbs or 48 oz

HELP ASAP ILL GIVE BRAINLIEST

Answers

Answer:

y=−2x−10

Step-by-step explanation:

Bart learned that the first stage of a type of rocket had a burn time that was 28.5 seconds longer than the burn time during the second stage. The total burn time for both stages was 150.3 seconds. What was they burn time for the first stage?

Answers

Answer:

60.9

Step-by-step explanation:

im prob not crct

if k=6 what is the value of 7k-2

Answers

Answer:

7x6-2=40

Step-by-step explanation:

Answer:

40

Step-by-step explanation:

7k -2 =

7(6) - 2

42 -2

40

You are welcome!

Kayden Kohl

8th Grade Student

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