Since Raj already has $68, he only needs $132. Because he has an hourly wage of $5.50, you would divide 132/5.50 to get the number or hours he still needs to work.
Raj still needs to work for 24 hours to be able to afford the video game system he wants.
However, at a wage of $6.25 per hour, he would only need to work 22 (21.12) more hours to afford the game system.
