Question

whats the probability that you will have to wait at least 20 minutes for a bus if it stops every 35 minutes

Answer 1

you can come to the bus station (or whatever it is called) in any time within 35 minutes.

only when you come in first 15 min (of the entire 35 min) will you have to wait 20 minutes or more.

So your probability is?

Answer 2

15/35 which is same as 3/7