Algorithms Quiz | SP Contest 4 | Question 1
A is running @ 20 m / s on a circular track of 400 m and B is running on the same track @ 16 m / s in opposite direction. After 5 minutes from starting how many times they have crossed each other on starting point?
(A) One time
(B) Two times
(C) Three times
(D) Four times
Explanation: Meeting for the first time on a circular track = LCM (circumference / speed of A, circumference / speed of B )
= LCM( 400 / 20, 400 / 16)
= LCM( 20, 25) = 100 sec.
In 100 second they will meet for the first time on starting point.
Similarly 2 time in 200 sec and after 300 sec(i.e. 5 minute) they had crossed each other on starting point 3 times.
So, option (C) is correct.
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