Ramesh rides along the boundary of a rectangular park at the rate of 12 km/hr and completes one full round in 15 minutes. If the length of the park is 4 times its breadth, then what is the area of the park?

let width=x and length=4x

perimeter of rectangular field=2(l+b)

distance=speed*time=12*15/60=3km

ramesh rides 3km of distance.

now,

3=2(4x+x)

3=10x

x=0.3km

length=1.2km and width=0.3km

area of rectangular field=0.3 * 1.2 = 0.36 square km