16Hit1600
AlgebraVery hardStarting altitude of a descending hiker

Algebra practice question

A hiker descends at a constant rate. She is at an altitude of 1,900 metres after 2 hours and 1,300 metres after 5 hours. At what altitude, in metres, did she start?

Answer: 2300

She descends 600 m in 3 hours, or 200 m per hour, so 2 hours before the first reading she was at 1,900 + 400 = 2,300 m.

Common wrong answers

If you answered 1500
1500 subtracts instead of adding.
If you answered 2100
2100 adds one hour's descent instead of two.
If you answered 2500
2500 adds three hours' descent.

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