Question

A train arrives at a station and waits 2 min before departing. Another train arrives at the station 18 minutes later, repeating the cycle. Identify the probability that a train will be at the station when you arrive.

Answer 1

`|\Omega|=20\\|A|=2\\\\P(A)=(2)/(20)=(1)/(10)=10\%`

Answer 2

1/10.

Explanation:

The length of each cycle is 2 + 18 = 20 minutes.

During this time the train in stationary for 2 minutes.

So the probability of the train being at the station when you arrive is 2/20 = 1/10.