Use the exponential decay model, Upper A equals Upper A 0 e Superscript kt, to solve the following. The half-life of a certain substance is 25 years. How long will it take for a sample of this substance to decay to 60% of its original amount?

18.42 years.

Step-by-step explanation:

We have been that the half-life of a certain substance is 25 years. We are asked to find time taken by substance to decay to 60% of its original amount.

We will use formula to solve our problem.

First of all, we will find value of k using , and .

Now we will take natural log of both sides of equation.

Our function would be .

Now we have and .

Now we will take natural log on both sides.

Therefore, it will take approximately 18.42 years for a sample of this substance to decay to 60% of its original amount

its kind of blurry. can you put a clearer pic?

step-by-step explanation:

answer: bearing in mind that a rectangle has a perimeter of length + length + width + width.

step-by-step explanation:

p = perimeter

l = length

x=width

p = 2l + 2x

p = 2(l+x)     < ==== perimeter of the base of the box.