Kiran is going to a carnival that has games and rides. Each game costs $1.50 and each
ride costs $3. Kiran spent $18 altogether at the carnival and the number of games he
played is 4 times the number of rides he went on. Write a system of equations that
could be used to determine the number of games Kiran played and the number of
rides Kiran went on. Define the variables that you use to write the system.