Pupils and teachers come from Gibson college went on an outgoing to London in 4 full coaches. Two teaches had to go by train. Unfortunately 3 of the coaches were parked illegally in London and their wheels were clamped. For the return journey there was one full coach and the other 143 pupils and the teachers had to go back by train. Use x to stand for the number of people in one full coach. Make an equation involving x and solve it to find the number of people on a coach

PL HELP