Question

retangular field is 90 m by 70 m. A man walks around it at the rate of 4 km per hour. What time will he take in making 5 rounds ?​

Answer 1

Step-by-step explanation:

speed = distance / time

note 1000m = 1km

let change unit of km/h to m/min

4km/h = 66.5m/min

time taken one round is

66.5m/min = 90/70 * x min

66.5* 70/90 = x

465.5/9

51.733 min

approximately 52 min

the time taken is

5 * 52 min

260 min Or 4 hrs 20 min

Answer 2

Perimeter of the rectangle is 90 + 90 + 70 +70 = 160 + 160 =320 m

In km we have 320/ 1000 = 0.320 km because 1000m = 1 km

So his speed = 4 km / hr = 4 km / 60 min = 1 km in 15 min .

5 rounds implies 5 ( 0.320 ) = 1.6 km

So if 1 km is 15 min then 1.6 km

15 × 1.6 min = 24 min

Hence the person takes 24 min .