Question

A, B and C start at the same time in the same direction to run around a circular stadium. A completes a round in 252 seconds, B in 308 seconds and c in 198 seconds, all starling at the same point After what time will they again meet at the starting point?
1. 26 minutes and 18 seconds
2. 42 minutes and 36 seconds
3. 45 minutes
4. 46 minutes and 12 seconds

Answer 1

Correct Answer - Option 4 : 46 minutes and 12 seconds

Given:

A completes the round in 252 seconds

B completes the round in 308 seconds

C completes the round in 198 seconds

Concept used:

Here we will use the concept of LCM

Calculation:

First find the factors

⇒ 252 = 2² × 3² × 7¹

⇒ 308 = 2² × 7¹ × 11¹

⇒ 198 = 2¹ × 3² × 11¹

LCM is

⇒ 2² × 3² × 7¹ × 11¹

⇒ 2772 seconds

Convert into minutes

⇒ 2772/60 = 46 minutes 12 seconds

∴ They will mee again in 46 minutes and 12 seconds.