Sathish is going on a 2100 km road with 2 friends, whom he will pick up 150 kilometers after he begins the trip and drops off wh
en 150 kilometers are remaining. The car consumes 6 liters of gas for every 100 kilometers and gas costs $1.20 per liter. Sathish will pay for all the gas when he is alone in the car, but he and his friends will split the cost evenly when they are together.
(x-2) 
is your equation