AlgebraEasy–MediumNet fill rate
Algebra practice question
A tank is empty. Water flows in at 12 litres per minute while a drain lets water out at 4 litres per minute. After how many minutes will the tank hold 200 litres?
Answer: 25
The net rate is 12 − 4 = 8 litres per minute: 8t = 200 → t = 25.
Common wrong answers
- If you answered 50
- 50 comes from 200 ÷ 4, using only the drain rate.
- If you answered 16.67
- 16.67 comes from 200 ÷ 12, ignoring the drain.
- If you answered 12.5
- 12.5 comes from 200 ÷ 16, adding the rates.
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