Algebra practice question

Answer: 6

Change in volume: −3m + 5(m + 4) = 32, so 2m + 20 = 32 and m = 6.

Common wrong answers

If you answered 16

16 comes from 2m = 32, forgetting the 20 litres from the extra 4 minutes of filling.

If you answered 26

26 comes from 2m − 20 = 32, subtracting the 20 instead of adding it.

If you answered 1.5

1.5 comes from 8m + 20 = 32, adding the rates instead of subtracting the drain.

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