Problem of the Week #3: Due on Sep 18

Riding the Rail
A monorail that crosses the amusement park leaves its western terminal at 9:05 a.m. and arrives at the eastern terminal at 9:35. It makes 3 stops along the route. The monorail left the terminal with 25 passengers on board. At the first stop, 5 passengers departed and 8 passengers boarded. At the second stop, 12 passengers departed and 8 passengers boarded. At the 3rd stop, 9 passengers departed and 6 passengers boarded. The monorail then proceeded without stopping to the eastern terminal.

Use the 4-step plan to solve: How many passengers were on the monorail when it arrived at the eastern terminal?