Question

The cost of levelling a circular field at 50 paise per square meter is Rs.7700. The cost of putting up a fence all round it at Rs.1.20 per meter is

• A. Rs.132
• B. Rs.264
• C. Rs.528
• D. Rs.1056

Answer 1

Answer:

C. Rs.528

$Amount=Area\times{Rate}$

$Area=\pi{r^2}$

$Rate = 50 paise=0.50$

$\pi{r^2}\times{0.50}=7700$

$\frac{22}{7}\times{r^2}\times{0.50}=7700$

$\frac{22}{7}\times{r^2}\times{\frac{50}{100}}=7700$

$\frac{2}{7}\times{r^2}\times{\frac{1}{2}}=700$

$r^2=4900$

$r=70$

Cost of Fencing,

$Perimeter \times{rate}=Amount$

$2\pi{r}\times{Rate}=Amount$

$2\pi{r}\times{1.20}=Amount$

$2\times{\frac{22}{7}}\times{70}\times{1.20}=Amount$

$Amount=2\times{12}\times{22}$

$Amount = 528$

Cost pf putting up fencing around id Rs.528.