AlgebraEasy–MediumWhole hours of video before an app closes
Algebra practice question
A phone's battery holds 7 units of charge, and playing video uses 2 units per hour. The video app closes as soon as the charge drops below 1 unit. For how many whole hours can the video play?
Answer: 3
7 − 2h ≥ 1 gives h ≤ 3.
Common wrong answers
- If you answered 2
- 2 hours leaves 3 units, so another hour is possible.
- If you answered 4
- 4 hours would leave −1 unit.
- If you answered 3.5
- 3.5 hours would drain the battery entirely, below the 1-unit cut-off.
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