Question

The dimensions of a rectangular field are 90 m x 70 m. A man walks around it at a uniform
speed of 4 km/hr. Find the time taken by him to go around the field five times​

Answer 1

Let length of field, l = 90m

Breadth of field, b = 70m

Perimeter of rectangle = 2(l + b)

Perimeter of rectangular field = 2(90 + 70) m

Perimeter of rectangular field = 2(160)m

Perimeter of rectangular field = 320m

Distance of 5 rounds along the field = (320 × 5)m

Distance of 5 rounds along the field = 1600m

Speed of man = 4 km/h

Total distance = 1600m

= 1600/1000 km

= 1.6 km

Time taken = distance/speed

Time taken = 1.6/4 h

Time taken = 0.4 h