Question

the half - life of a particular radioactive substance is 1 year. if you started with 40 grams of this substance, how much of it would remain after 3 years? remaining amount = ?(1 - )^ remaining amount = i(1 - r)^t enter the number that belongs in the green box.

Explanation:

Step1: Identify the initial amount

The initial amount $I$ of the radioactive - substance is 40 grams. This is the value that goes in the green box in the formula $Remaining\ Amount = I(1 - r)^t$.

Step2: Identify the decay rate

The half - life is 1 year. In the formula $Remaining\ Amount = I(1 - r)^t$, for a half - life situation, the decay rate $r=\frac{1}{2}=0.5$.

Step3: Identify the time

The time $t = 3$ years. But we are only asked for the value in the green box which is the initial amount.

Answer:

40