4
lesson pretestMultiple Choice

Pretest

Question 4 • CMS 2026-2027 NC Math 1 CREDIT RECOVERY

A scientist has 400 grams of a radioactive substance with a half-life of one year. The amount of the substance that the scientist has after t years is represented by the expression 400 times 0 point 5 to the t th power Which kind of expression is 400 times 0 point 5 to the t th power ?

Answer
A
exponential decay
B
quadratic
C
linear
D
exponential growth

Explanation

The expression is 400 × 0.5^t, so the amount is multiplied by 0.5 for each passing year. Because 0.5 is between 0 and 1, the amount gets smaller over time. This is exponential decay, so the correct choice is D, exponential decay.

AI-written and checked against the verified answer.

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