Set 3: Exponential Functions (Advanced)

[Variation 1] **Choice C is the best answer.** After 2 half-lives: 320 / 2 to the power of 2 = 80 grams

Explanation

Answer: C

PROBLEM

Recent studies show that a substance with half-life of 1 hour starts at 320 grams. How many grams remain after 2 hours?

A substance with half-life of 1 hour starts at 320 grams. How many grams remain after 2 hours?

160

✓ Correct

Detailed Explanation

[Variation 1] Choice C is the best answer. After 2 half-lives: 320 / 2 to the power of 2 = 80 grams

Why others are wrong:

A: 79 is incorrect because it does not satisfy the equation.

B: 160 is incorrect because it does not satisfy the equation.

D: 82 is incorrect because it does not satisfy the equation.