Question

THE AREA OF RECTANGULAR FIELD IS 3584m² and its length is 64cm. A boy runs around the field at the rate of 6 km/hr. How long will it take to go 5 times around it.??????? ​

Answer 1

Breadth of the field = Area/length = 3584/64 = 56m

Perimeter of the field = 2*(64+56) = 240m

The boy covers five rounds of the field so the total distance covered by the boy = 240*5 = 1200m or 1.2km

Now time = distance/speed = 1.2/6 = 0.2 hrs = 12min

So the boy will go five times around the field in 12 min

Answer 2

ANSWER :-

Given :-

$\rm{area \: of \: field = 3584 \: m </p><p>^2</p><p> }$

$\rm{length = 64 m}$

We know

$\rm \boxed{\red{area = length × breadth = l×b}}$

$\rm{b= \dfrac</p><p>{3584}{64}}</p><p>$

$\rm{b =56 \: m}$

$\rm{Now \: Perimeter \: of \: field = 2[l+b]} \\ \rm{ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: </p><p>=2[64+56]}$

$\rm{Perimeters \: of \: field = 2[120]= 240 m.}$

$\rm{for \: 5 \: rounds \: perimeter = 240×5=1200m}$

$\rm{Given \: speed \: of \: boy = 6 km/h = 6× \dfrac{5}</p><p>{18}</p><p></p><p> </p><p> = \dfrac</p><p>{</p><p>5}{3}</p><p> </p><p> m/sec}$

$\rm{then \: time \: taken \: to \: cover \: 1200 \: m \: distance = \dfrac{1200}</p><p>{5}</p><p></p><p> </p><p> ×3}$

$\rm{Time = 240×3 \: sec}$

$\rm{or \: Time = \dfrac {240}</p><p>{60</p><p>}×3</p><p> </p><p> min=12min}$

$\rm \underline{ \underline{\green{∴ \: 12 \: min \: required \: to \: complete \: 5 \: rounds \: of \: field.}}}$