A) Rs. 1200
B) Rs. 1800
C) Rs. 900
D) None of these
Correct Answer: C
Solution :
Cost = Rs.160 per hectare \[=2\pi rh\] [We have 1 hectare = 10,000 square meter] Area of the field \[=2\pi r(h+r)\] hectare \[=\frac{1}{3}\pi {{r}^{2}}h\] If 'a' denotes the side of the field (or square), then \[=\pi rl.\]\[l=\sqrt{{{h}^{2}}+{{r}^{2}}}\] \[=\pi rl+\pi {{r}^{2}}=\pi r(l+r)\] \[\frac{1}{3}rd\] Perimeter of the field = 4a = 1200 m Now, the cost of putting a fence \[=\pi {{r}^{2}}h-\frac{1}{3}\pi {{r}^{2}}h=\frac{2}{3}\pi {{r}^{2}}h=\frac{2}{3}\times \frac{22}{7}\times 6\times 6\times 14\] \[=1056c{{m}^{3}}.\]
You need to login to perform this action.
You will be redirected in
3 sec
