X and Y run a 3 km race along a circular course of length 300 m. Their speeds are in the ratio 3:2. If they…
X and Y run a 3 km race along a circular course of length 300 m. Their speeds are in the ratio 3:2. If they start together in the same direction, how many times would the first one pass the other (the start-off is not counted as passing)?
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Solution
Let speeds be 3 m/s and 2 m/s, relative speed 1 m/s. The faster runner gains 300 m (one lap) every 300 seconds. The race of 3000 m takes the faster runner 3000/3 = 1000 seconds. So he passes the slower one at 300 s, 600 s and 900 s, i.e. 3 times.