Question

The length and breadth of a playground are $80m$ and $35m$ respectively.
How long will a boy take to go three times round the field, if he walks at rate of $1.5m$ per second ?

Answer 1

Given length of playground = 80 m

width of playground = 35 m

Perimeter (length of boundary) = 2(l+b)

$=2(80+35)=115\times 2$

length of boundary = 230 m

For 3 rounds length = $230\times 3=690m$

now time taken to boy to cover 1.5 m = 1 sec

then time taken to cover 690 m = $\frac{6900}{1.5}$

Total time taken = 4600 sec

$\therefore$ Time taken to complete 3 rounds of field is 4600 seconds.