Arjun can complete a round of a circular track in 72 seconds. Birju, running in opposite direction c

M4maths Previous Puzzles

07 Jun 2022 Time Distance & Speed

Arjun can complete a round of a circular track in 72 seconds. Birju, running in opposite direction crosses Arjun at every 18 seconds, then Birju can complete a round of circular track in (sec)

OPtion

1) 30
2) 54
3) 27
4) 24
5) 21
6) 28
7) 16
8) 48
9) 36
10) None of these

Solution

Let t = Birju′s time in seconds to complete 1 round.
Let L represent the length of the track, then speed of Arjun = L/72 and Birju = L/t
We have (L/72)*18 + (L/t)*18 = L
⇒ t=24 sec

Correct Option: 4 Best Solution (1)