# math

posted by anuj

A boy is cycling such that the wheels of the cycle are revoloving 140 times per minute.if the diameter of the wheel is 60 cm,calculate the speed per hour with which the boy is cycling. Find answer in km per hour

1. Arora

Step 1:
Circumference of the wheel = 2*pi*r
= pi*d
= 3.14 * 60 cm
= 188.4 cm
= 1.884 m

Step 2:
How much distance is being traveled each minute?
140 revolutions = 140 circumferences per minute
= (1.884*140) meters per minute
= 263.76 m per minute
= 4.4 m per sec

Step 3:
Convert m/s to km/h
=> 4.4 m/s
= 1.22 km/h

2. Scott

264 m/min * 60 min/hr = 15.8 km/hr

4.4 m/s * 3600 s/hr = 15.8 km/hr

final conversion went awry

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