Question

A rectangular field is 72 m 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

Dimensions of a rectangular field= 72cm y 58cm

perimeter of the rectangular field= 2( l+b )

                                                   =2×( 72+58)

                                                   = 2×130

                                                   =  260cm

∴ Distance taken by Amar in taking two rounds= 2×260m

                                                                          = 520m

Speed of Amar= 3km/hr

                       =3×1000/3000 m/sec 

                       = 5/6 m/sec

Total time taken by Amar to cover the distance= Distance/speed

                                                                         = 520/5/6 = 520×5/6

                                                                         = 104×6

                                                                         = 104×6/60 min.

                                                                         = 10.4 min.

Answer 2

Answer:

Length = 72m=0.072km

Breadth= 58m=0.058km

Speed =3km/h

Time =distance /speed

Distance= perimeter of rectangle.

Perimter=2(0.072+0.058)

=2*0.13

=0.26km

Therefore time =0.26/3

= 0.866 hour

For 1 round time = 0.866

Therfore, for 2 rounds =2*0.866

= 1.7 hours