How long will a boy take to go, walking 3km/h once round a circular park 420 m in diameter

How long will a boy take to go, walking 3km/h once round a circular pa

1.	How long will a boy take to go, walking 3km/h once round a circular park 420 m in diameter
Answer» Perimeter of circle = 2Πr And diameter =420m Therefore radius=210mPerimeter=(222210)/7 =22230 = 1320mA/Q Speed of the boy=3km/hour=> Distance covered by boy in 1 hour=3km =3000m Now, Time taken to cover 3000m = 1hour Time taken to cover 1m= 1/3000hours Time taken to cover 1320m= (1/3000)*1320 = 0.44 hoursTherefore Time taken by the boy is 0.44 hours or 26.4 mins