16Hit1600
Advanced MathEasy–MediumDoubling repeatedly

Advanced Math practice question

A single bacterium culture starts with 20 cells and doubles in number every hour. How many cells are there after 4 hours?

Answer: 320

20 × 2⁴ = 20 × 16 = 320.

Common wrong answers

If you answered 80
80 multiplies 20 by 4 (linear, not doubling).
If you answered 160
160 is after 3 hours.
If you answered 640
640 is after 5 hours.

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