Question

The length and breadth of a playground are 75 m and 45 m respectively. How long will a boy take to go four times around the field if he walks 2 m per second?

Answer 1

Path length for one round
$= 2(l + b)$
l = 75 , b = 45m
$= 2(l + b) \\ = 2(75 + 45) \\ = 2(120) \\ = 240m$
Path length for 4 round,
$= 4(path \: length) \\ = 4(240) \\ = 960m$
Distance = 960m , Speed = 2m/s

$time \: taken = \frac{distance}{speed} \\ = \frac{960}{2} = 480s \\ or \: 8 \: minutes$