The radii of the front wheel and the rear wheel of a bike are 14 cm and 21 cm respectively. Rahul puts a red… · ABC26GN4581
Subject: General Aptitude · Chapter: Area
The radii of the front wheel and the rear wheel of a bike are 14 cm and 21 cm respectively. Rahul puts a red mark on the point of contact of each of the wheels with the ground when the bike is stationary. Once the bike starts moving, then after what distance will the two red marks touch the ground again simultaneously?
(a)42 cm
(b)84 cm
(c)264 cm
(d)294 cm
Answer
Answer (as printed): C
Explanation
Circumference of the front wheel $=\left(2 \times \frac{22}{7} \times 14\right) \mathrm{cm}=88 \mathrm{cm}$. $$\text { Circumference of the rear wheel }=\left(2 \times \frac{22}{7} \times 21\right) \mathrm{cm}=132 \mathrm{cm} .$$ Required distance = L.C.M. of 88 cm and 132 cm = 264 cm.