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)^3 remaining amount = ? grams round your answer to the nearest whole number.

Explanation:

Step1: Calculate the value inside the parentheses

$1 - 0.50=0.50$

Step2: Calculate the exponentiation

$0.50^3 = 0.50\times0.50\times0.50 = 0.125$

Step3: Multiply by the initial amount

$70\times0.125 = 8.75$

Step4: Round to the nearest whole number

Rounding $8.75$ to the nearest whole number gives $9$.

Answer:

$9$