As far as cost and safety are concerned, train and plane provide equally good ways of getting from Toronto to Montreal. The trip takes four hours by train and one hour by plane unless Dorval (the closer airport to Montreal) is fogged in, in which case the plane trip and the ride in from Mirabel (the further airport) take four hours. If both airports are fogged in the plane will land in Ottawa and the trip will take five hours. There is a 60% chance that Dorval will be fogged in and a 30 % chance that both Dorval and Mirabel will be fogged in. Decide whether to take the plane or the train.

*going for which method of travel will be shorter*

Can anyone give this a shot? :) need some help with this

You need to calculate the expected value of the plane ride duration. There are three possibuilities: the trip takes 1 hour, 4 hours, or 5 hours. Multiply each of these values by the probability of it occurring, and add up the result. This gives the expected value, and if it's less than the train duration it's better (on averege) to take the plane.