VeritasPrepKarishma wrote:
noboru wrote:
A man cycling along the road noticed that every 12 minutes a bus overtakes him and every 4 minutes he meets an oncoming bus. If all buses and the cyclist move at a constant speed, what is the time interval between consecutive buses?
5 minutes
6 minutes
8 minutes
9 minutes
10 minutes
5 minutes
6 minutes
8 minutes
9 minutes
10 minutes
There is only one thing you need to understand in this question - When buses are approaching him from both the sides at a constant speed, it doesn't matter whether the man is standing still or cycling, the number of buses that he will meet will be the same. Convince yourself by imagining the case where the man is standing still. He will meet a bus from each side after every few mins. When he starts cycling in a direction, he is cycling away from buses of one side but towards buses of the other side. Since in 12 mins he meets total 4 buses (1 + 3), in 6 mins he meets 2 buses, one from each side, if he were standing still. So buses ply at a frequency of 6 mins each.
Twist: Same scenario. If a man is sitting inside one bus, at what frequency will a bus from opposite side cross him?
Also try the same question by changing the time taken by buses to meet the man to 10 min and 8 min respectively (instead of 12 mins and 4 mins)
Hi,
I am not able to understand how did you arrive at 2 buese in every 6 mins. I do agree that in 12 mins there will be 4 buses but how did you come to the conclusion of 2 buses in every 6 minutes and that too from one from each side. Can you please clarify.