Question

Three wheels can complete 25, 21 and 16 revolutions per minute respectively. There is a red spot on each wheel that touches the ground at time zero. After how much time, all these spots will simultaneously touch the ground again?

• A. \(58 \text{ seconds} \)
• B. \(60 \text{ seconds} \)
• C. \(62 \text{ seconds} \)
• D. \(59 \text{ seconds} \)
• E. \(61 \text{ seconds} \)

Hint:

For problems involving rotations: - Convert speeds to time per revolution - Then take LCM to find when events coincide

Answer 1

The Correct Option is B