Question

a rectangular field is 72m by58m. Amar walks round it at the rate of 3km 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

length=72 m
breadth=58 m
perimeter= 2(l+b)
=2*(72+58)
=2*130
=260m

total distance to be covered=2 rounds=2*260m=520m

speed=3km/hr=3*5/18=5/6. m/s

time taken = distance/speed
=520*6/5=3120/5
=624 sec
=10 minutes 24 sec