Question

A man riding a bicycle completes one lap of a circular field along its circumference at the speed of 14.4 km/hr in 1 minute 28 seconds . What is the area of the field ?
A. 7958 sq mt
B. 9856 sq mt
C. 8842 sq mt
D. Cannot be determined

Answer 1

Correct Answer - B
14.4 km/hr = `(14.4 xx (5)/(8))` = 4 m/s
Total time = `(60 + 28 ) = 88` s
Total distance = `4 xx 88 = 352`
Circumference = 352 m
or , `2 pi r = 352` m
or , `2 xx (22)/(7) xx r = 352` m
or , r = `(352 xx 7)/(22 xx 2) = 56` m
Now , area of circle = `pi r^(2) = (22)/(7) xx 56 xx 56`
= `9856 m^(2)`