A culture of 500 bacteria doubles every 3 hours. How many are there after 9 hours?
Answer and explanation
Correct answer: C. 4000, from 500(2)^3
- Step 1: 9 hours is 9/3 = 3 doubling periods. Step 2. 500 x 2^3 = 500 x 8 = 4000. Answer: 4000. Why not the others: growth by doubling is multiplicative, not additive, and 3 doublings are needed.
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