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 - ?)^ remaining amount = i(1 - r)^t enter the number that belongs in the green box.

Explanation:

Step1: Identify decay rate

The half - life is 1 week. In the formula $A = I(1 - r)^t$, for a half - life situation, the decay rate $r=\frac{1}{2}$.

Step2: Identify time period

The time $t$ is 3 weeks.

Answer:

$\frac{1}{2}$