A bacteria colony of 500 cells doubles every 3 hours. How many cells are there after 9 hours?
Answer and explanation
Correct answer: A. 4000
- Step 1: 9 hours contain 9/3 = 3 doublings.
- Step 2: 500 x 2^3 = 4000.
Answer
4000.
Why not the others: Doubling means multiplying by 2 each period, not adding a fixed amount; counting one doubling per hour gives far too many.
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