Question

A wheel has diameter $84cm$. Find how many complete revolutions must it make to cover $3168km$.

• A. $1200$
• B. $2200$
• C. $1250$
• D. $1100$

Answer 1

The correct option is A $1200$

Diameter of wheel=$84cm$
Therefore,
Radius of wheel=$42cm$
Wheel travels $2\pi r$ distance in one revolution.
$\therefore$Wheel travels $3168km$ distance in$\frac{1\times 3168km}{2\pi rcm}$

$=\frac{3168\times 7\times 100}{2\times 22\times 42}$

$=1200$