Joy and Kat run around a circular track of length 1100 m in opposite directions with an initial speed of 6 m/sec and 4 m/sec, respectively. Starting from the same point whenever they meet, Joy’s speed halves and Kat’s speed doubles. After how much time from the beginning will they meet for the second time?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 210 sec.
Relative speed = 6 + 4 = 10 m/s
Time = 1100/10 = 110 sec
After 1st meeting: New speeds: Joy = 3 m/s, Kat = 8 m/s
Relative speed = 3 + 8 = 11 m/s
Time for 2nd meeting = 1100/11 = 100 sec
Total Time = 110 + 100 = 210 sec