Question

A big group of people are taking the train home for Christmas. 19 people get off the train in Brooklyn, 17 people then get on. Now there are 63 people on the train. How many were there to begin with

Answer 1

There were 65 people to begin with.
If you have 65 people, 19 get off you then have 46. 
Then 17 get on... You then have 63 people on the train.