Question

thwe area of a rectangular field is 3584m and its length is 64m .A boy runs around the field at the rate of 6km/h how long will he take to go 5 times around it

Answer 1

let the breadth be 'x'

leght = 64 m

area of rectangular field = l * b

3584 = 64 * x

3584/64 = x

56 m = x

breadth = 56 m

perimeter of the field = 2(l+b)

= 2(64+56)

= 2(120)

= 240 m

speed of the boy = 6km/h

time =distance/speed

= 240*5*60/6000

= 12 mins

the boy takes 12 mins to go 5 times around the field

Answer 2

given, area of rectangular field =3548sq.m
length L =64m
let the breadth of the rectangular field =B
area =3584
64x b=3584
B =3584/64
B =56m
since the boy run around a rectangular field, then the distance he travels should be equal to the perimeter of the rectangle
perimeter =2(L+B)
=2x(56+64)
=2x120
=240m
since the boy run 5 rounds, then the distance travelled =5x240=1200m
speed of the boy =6km/h=6x1000/60x60m/sec
=1.66m/sec
let the time taken by the boy =T
time T=1200/1.66
T=723sec ( approx)
or,T=723/60
T=12.05mins.