Question

If a bicycle wheel makes $5000$ revolution in moving $11$ km, then diameter of wheel is

• A. $110$ cm
• B. $120$ cm
• C. $70$ cm
• D. $100$ cm

Answer 1

The correct option is C $70$ cm

Let radius of wheel be $r㎝$. Then, distance travel in $1$ revolution$=2\pi r$

Total distance$=11㎞=1100m=1100000㎝$

Total revolutions$=5000$

$\Rightarrow 5000\times 2\pi r=1100000\Rightarrow r=\frac{1100000\times 7}{2\times 22\times 5000}=35㎝$

$\therefore$Diameter of wheel $=2\times 35=70㎝$