The first car of the D-line train carried 1.5 times the number of passengers that the second car carried. Three passengers get out of the first car at Newton Center and two passengers get into the second car at the same station. After this stop both cars had an equal number of passengers. How many passengers were in each car before the Newton Center stop?

Answer 1

start writing what they tell you. If the 1st car had 3x and the 2nd car had 2x (because the ratio was 3:2) then
3x-3 = 2x+2
x = 5
So the two cars had 15 and 10 passengers, respectively.
Check: 15-3 = 10+2