Question

a rectangular field is 72m by 58m. amar walks round it at the rate of 3 km per hour. What time will he take in taking 2 rounds?​

Answer 1

Perimeter of rectangle = 2(l*b)

therefore, P = 2(72*58)

= 260

260m = 0.26km or 1km = 1000m

so if amar walks at the speed of 3km per hour ;

(1 * 260) / 3000 = 11.53

Answer 2

Given, dimensions of a rectangular field :

Length $(l)=72m$.

Breadth $(b)=58m$.

Amar walks round the field at the rate of $3 km/hr.$

We know that, formula for perimeter of a rectangle $=2\times(l+b)$.

$\implies$ perimeter $=2\times(72+58)$

$\implies$ perimeter $=2\times130$

$\implies$ perimeter $=260m$.

Let us convert the meters to kilometres.

We know that, $1000m=1km \implies 1m= \frac {1} {1000} km$.

So, $260m= \frac {260} {1000} km =0.26km$.

Therefore, perimeter of a rectangular field is $0.26km$.

Speed of Amar is $3 km/hr.$

We know that, speed $= \frac {distance} {time}$

$\implies 3= \frac {0.26} {time}$

$\implies$ time $= \frac {0.26} {3}$

$\implies$ time $=0.087 hrs.$

$\implies$ time $=0.087\times 60=5.22$ minutes. (since, $1 hour =60$ minutes).

Here, time taken for Amar for one round around the field is $5.22$ minutes.

So, time taken for two rounds $=2\times 5.22=10.44$ minutes.

Hence, time taken by Amar to walk $2$ rounds around the rectangular field is $10.44$ minutes.