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gayaneshka [121]

3 years ago

14

Derek invested 1,500 into an account that pays 9% intrest compounded monthly. How long must the money be left in the account for

it to grow 2,147.11?

1 answer:

Usimov [2.4K]3 years ago

4 0

4.79 Months, each month he gains 135 dollars so I subtracted the difference then divided by 135

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2.The number of grams A of a certain radioactive substance present at time, in yearsfrom the present, t is given by the formulaA

professor190 [17]

Answer:

Given that,

The number of grams A of a certain radioactive substance present at time, in years

from the present, t is given by the formula

$A=45e^{-0.0045(t)}$

a) To find the initial amount of this substance

At t=0, we get

$A=45e^{-0.0045(0)}$ $A=45e^0$

We know that e^0=1 ( anything to the power zero is 1)

we get,

$A=45$

The initial amount of the substance is 45 grams

b)To find thehalf-life of this substance

To find t when the substance becames half the amount.

A=45/2

Substitute this we get,

$\frac{45}{2}=45e^{-0.0045(t)}$

$\frac{1}{2}=e^{-0.0045(t)}$

Taking natural logarithm on both sides we get,

$\ln (\frac{1}{2})=-0.0045(t)^{}$ $(-1)\ln (\frac{1}{2})=0.0045(t)$ $\ln (\frac{1}{2})^{-1}=0.0045(t)$ $\ln (2)=0.0045(t)$ $0.6931=0.0045(t)$ $t=\frac{0.6931}{0.0045}$ $t=154.02$

Half-life of this substance is 154.02

c) To find the amount of substance will be present around in 2500 years

Put t=2500

we get,

$A=45e^{-0.0045(2500)}$ $A=45e^{-11.25}$ $A=45\times0.000013=0.000585$ $A=0.000585$

The amount of substance will be present around in 2500 years is 0.000585 grams

4 0

9 months ago

What is the mean of 5,5, 8,10

TiliK225 [7]

So, when doing this kind of problems, the first thing that we would want to do is to add up (all) the numbers first, and by doing this, it would look like the following:

$5+5+ 8+10=28$

Then, we would then divide it by how many numbers they are.

$\boxed{28\div4} \ =7$

Your answer: 7

7 0

2 years ago

Read 2 more answers

⦁ Find the distance between the two numbers

Temka [501]

1. 12+19=31
2. -14
3.0

8 0

2 years ago

Read 2 more answers

What is the value of 5-8×(7-15+8)

salantis [7]

Answer:

I'm pretty sure that the answer is 5. Correct me if i'm wrong

Step-by-step explanation:

6 0

2 years ago

Write and simplify an expression to model the relationship expressed in the situation below.

spayn [35]

V(p) = x-n, where V(p) is the volume after the boxes have been together, x is the volume of the larger box, and n is the volume of the smaller box.
x = 15 cm x 25 cm x 20 cm = 7500 cubic centimeters (cm^3)
n = 10 cm x 10 cm x 10 cm = 1000 cm^3
V(p) = 7500 - 1000 = 6500 cm^3
So your answer is 6500 cubic centimeters.

6 0

3 years ago