Question

the half - life of a particular radioactive substance is 1 week. if you started with 70 grams of this substance, how much of it would remain after 3 weeks? remaining amount = 70(1 - 0.50)^? remaining amount = i(1 - r)^t enter the number that belongs in the green box.

Explanation:

Step1: Identify the number of half - lives

The half - life is 1 week and the time elapsed is 3 weeks. The number of half - lives $n=\frac{3}{1}=3$.

Step2: Determine the exponent in the formula

In the formula $Remaining\ Amount = I(1 - r)^t$, the exponent $t$ represents the number of half - lives. Here, $t = 3$.

Answer:

3