Races - Quant/Math -
Question 4 the day:
November , 2002
The question for the day is from the topic of Races.
- Three friends A, B and C run around a circular track of length 100 m at 5 m/sec, 8 m/sec and 10 m/sec speeds starting from the same point, simultaneously and running in the same direction. When will they be again together?
| (1) |
50 seconds |
|
(2) |
500 seconds |
|
(3) |
300 seconds |
|
(4) |
100 seconds |
Correct Answer - (4)
Solution:
Let A run at 5 m/sec, B run at 8 m/sec and C run at 10 m/sec.
A and C will be together every 20 seconds.
B and C will be together every 50 seconds.
Therefore, all 3 of them will be together at the LCM of the time taken for each of the pairs to be together.
LCM of 20 and 50 = 100.
|