Question

A wheel has diameter 84 cm. Find how many complete revolutions must it make to cover 3.168 km.

• A. 1020
• B. 1200
• C. 1002
• D. 120

Answer 1

The correct option is B 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$\frac{1\times 3168km}{2\pi rcm}$
$=\frac{3168\times 7\times 100}{2\times 22\times 42}$
$=1200$