Question
Reshma covers 45 km at a speed of 15 km/h by bicycle, 80
km at a speed of 40 km/h by car, and another 6 km at a speed of 2 km/h on foot. Find her average speed for the whole journey (correct to 2 decimal places).Solution
ATQ, we can say that Reshma covers first 45 km at the speed of 15 km/hr she covers next 80 km at the speed of 40 km/hr. she covers next 6 km at the speed of 2 km/hr Formula used: Average speed = Total distance/Total time Calculation: Total distance covered = 45 + 80 + 6 = 131 km Total time = (45/15) + (80/40) + (6/2) = 3 + 2 + 3 = 8 hr ∴ Average speed = 131/8 kmph = 16.375 or 16.38km/hr
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