Physicshard · Past Paper

A car travels 1/3 distance with 10 km/h, 1/3 with 20 km/h and 1/3 with 60 km/h. Average speed is:

A18 km/h
B30 km/h
C25 km/h
D20 km/h

✓ Correct Answer: A18 km/h

Avg Speed = 3 / (1/10 + 1/20 + 1/60) = 3 / (6+3+1)/60 = 180 / 10 = 18 km/h.

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