Question

The diameter of a bullock cart wheel is $\frac{14}{11}$ metres This wheel makes ten complete revolutions per minute What would be the speed of the cart in kilometres per hour

• A. $4.8$
• B. $9.6$
• C. $8.8$
• D. $2.4$

Answer 1

The correct option is D $2.4$

Radius $=\frac{1}{2}\times \frac{14}{11}=\frac{7}{11}m$
$\therefore$ Perimeter $=2\pi r=2\times \frac{22}{7}\times \frac{7}{11}m=4m$
Thus the wheel covers 4 meters in one revolution i.e. $40$ meters in $10$ revolutions Hence the distance of meter is covers in one minute i.e. $2400$meter in $40$ minutes i.e. $2.4$ km in one hour