Question

the area of a rectangular field is 3584 m square and its length is 64 M A boy runs around the field at the rate of 6 km per hour how long will it take to go 5 times around it.

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Answer 1

breadth=3584/64

56

perimeter =2(l+b)

2(64+56)

120x2=240m

total track length in 5 times=240x5

1200m

time=1.2km/6

0.2=12min

Answer 2

Area of rectangle=

$l \times b \\ area = 3584m^{2} \\ 3584 = 64 \times b \\ b = \frac{3854}{64} \\ b = 56m \\ perimeter = 2(l + b) \\ = 2(64 + 56) \\ =240m= 0.24 km$

$area \: covered \: in \: 1 round = 0.24m \\ area \: covered \: in \: 5 \: rounds \\ = 5 \times 0.24 = 1.2km \\ speed \: of \: the \: boy \: = \: 6kmh^{ - 1} \\ speed = \frac{distance}{time} \\ 6 = \frac{1.2}{time } \\ time = \frac{1.2}{6} = 0.2 \: hour \\ = 0.2 \times 60 = 12 \: minutes$