Question

Suppose that the half-life of a substance is 250 years. If there were initially 100 grams, how much of the substance will remain after 500 years?

A) 25 grams
B) 50 grams
C) 75 grams
D) 100 grams

Answer 1

After 500 years, 25 grams of the substance will remain.

Step-by-step explanation:

We know that the half-life is the time it takes for half of a sample to change. In this case, the half-life of the substance is 250 years. So, after 250 years, half of the initial amount (50 grams) will remain. After the next 250 years, half of the remaining amount (25 grams) remains. Therefore, after 500 years, 25 grams of the substance will remain from the initial 100 grams. After another 250 years (500 years total), half of the remaining 50 grams will decay, leaving only 25 grams of the substance.