The formula for probabilty is given by; the Probability of an event(A) is the number of favorable outcomes divided by the total number of outcomes possible in a scenario. It can also be denoted by the formula:
In our problem we have 16 trains that are full and 4 which are not, therefore there are a total number of 20 trains in the Westford Station.
The number of favorable outcome is equal to the number of trains that are full since it is the one asked in our question as the one which is more favored to come, according to the question.
Therefore, the number of favorable outcome = number of full trains = 16, and
The Total number of Outcome = total number of trains that may pull over to Westford Station = 20
Therefore the experimental probability that a full train will pull over in the station is;
Therefore there is a probabilty of 4/5 or 80% that a full train will pull over the station.