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From a point on a circular track 5 km long A, B and C started running in the same direction at the same time with speed of 21/2 km per hour, 3 km per hour and 2 km per hour respectively. Then on the starting point all three will meet again after
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- 30 hours
- 6 hours
- 10 hours
- 15 hours
Correct Option: C
A makes one complete round of the circular track in
| = 2 hours, | ||
| 5 | ||
| 2 |
| B in | hours and C in | hours. | ||
| 3 | 2 |
That is after 2 hours A is at the starting point,
| B after | hours and C after | hours. | ||
| 3 | 2 |
| Hence the required time = LCM of 2, | and | hours | ||
| 3 | 2 |
| Required time = | HCF of 1 , 3 , 2 |
| Required time = | = 10 hours. | 1 |
