Question

a field is in the form of a circle A fence is to be erected around the field the cost of fencing would be rupees 2640
@ rupees 10 per metre then the field is to be thoroughly ploughed @ rupees 0.50 per metre square what is the amount required to plough the field take Pi is equal to 22 by 7 ​

Answer 1

Total cost of fencing the circular field = Rs. 2640

Cost per metre fencing = Rs 12 Total cost of fencing = circumference x cost per fencing ⇒ 2640 =

circumference x 12 ⇒ circumference = 2640/12=220m

Let radius of field be r m

Circumference = 2πr m

2πr = 220 2 x 22/7 x r = 220 r = 70/2=35m

Area of field = πr2 = 22/7x35x35 = 3850 m2.

Cost of ploughing per m2 land = Rs. 0.50

Cost of ploughing 3850 m2 land = 1/2 x 3850 = Rs. 1925.

Answer 2

$length \: of \: the \: fence \: =$

$\frac{total \: cost}{rate \: of \: interest \:} = \frac{2640}{12} = 220m$

$therefore \: 2\pi \: r \: = 220m$

==>

$r = 35m$

Therefore,

$area \: = \pi {r}^{2} = \pi(35) {}^{2}$

COST OF PLOUGHING THE WHOLE FIELD =

$rs \: \: \: {pi(35) }^{2} \times 0.50$