Question

The inner circumference of a circular tracks is $220m$. The track is $7$ $m$ wide everywhere. Calculate the cost of putting up a fence along the outer circle at the rate of Rs. $2$ per metre. Use $\pi =\frac{22}{7}$

• A. Rs. $947$
• B. Rs. $726$
• C. Rs. $612$
• D. Rs. $528$

Answer 1

The correct option is D Rs. $528$

Circumference of inner side = $220m$

$\Rightarrow 2\pi r=220\Rightarrow r=\frac{220\times 7}{44}=35m$

Now, width of track $=7m$

$\therefore$ Outer radius $=35+7=42m$

Therefore outer circumference $=2\pi R=2\times \frac{22}{7}\times 42=264m$

$\therefore$ Cost of fencing $=$ Rs. $(264\times 2)$ $=$ Rs. $528$