Question

A field is in the form of circle. A fence is to be erected around the field. The cost of fencing would to Rs. 2640 at rate of Rs.12 per metre. Then the field is to be thoroughs ploughed at cost of Rs. 0.50 per m2. What is amount required to plough the field?

Answer 1

Given

Total cost of fencing the circular field = Rs. 2640

Cost per metre fencing = Rs 12

Total cost of fencing = circumference × cost per fencing

⇒ 2640 = circumference × 12

⇒ circumference =`2640/12`= 220𝑚

Let radius of field be r m

Circumference = 2 𝜋r m

2𝜋r = 220

2 ×`22/7`× 𝑟 = 220

r = `70/2`= 35𝑚

Area of field = 𝜋r²

^{=`22/7`× 35 × 35}

^{= 3850 m2.}

^{Cost of ploughing per m2 land = Rs. 0.50}

^{Cost of ploughing 3850 m2 land =`1/2`× 3850}

^{= Rs. 1925.}