The half-life of polonium is 139 days, but your sample will not be useful to you after 89% of the radioactive nuclei present on the day the sample arrives has disintegrated. For about how many days after the sample arrives will you be able to use the polonium?

You will be able to use the sample for about 441 days.

Step-by-step explanation:

The equation for the amount of polonium after t days is given by:

In which P(0) is the initial amount and r is the rate of decrease.

The half-life of polonium is 139 days

This means that .

We apply this to the equation, and find r.

Applying ln to both sides of the equality:

So

So

Your sample will not be useful to you after 89% of the radioactive nuclei present on the day the sample arrives has disintegrated. For about how many days after the sample arrives will you be able to use the polonium?

It will be useful until t in which . So

Applying ln to both sides

You will be able to use the sample for about 441 days.

the answer is:

the correct option:

b.

to solve the problem, we need to remember how to operate to simplify exponential expressions using the logarithms.

we are given the equation:

then, using placing logarith with base 7 on both sides of the equation, we have:

so, rounding the obtained result to two decimal places (nearest hundreth), we have:

hence, we have that the correct option:

b.

have a nice day!

we know that

major arc is defined as the bigger arc connecting two points on the edge of a circle. measure of major arc is always more than ° or π radian

in this problem

the mayor arc is bac

find the ratio of the measure of the major arc to the measure of the minor arc

therefore

the answer is the option