The length of a rectangular field is twice its width. Ramesh jogged around it 5 times and covered a distance of 3 km.

What is the length of the field?

let width=x then length=2x

perimeter of rectangle=2(length+width)

3km=3000m

3000=5[2(2x+x)]

3000=10*3x

30x=3000

x=100

so length=2*100=200m