Rule: ((X•6)•9)
Key: X=number of hours worked.
You can check your rule by using the number 1 to represent the letter X in your rule. This would make it ((1•6)•9). 1•6=6, and then 6•9=54. This is how you know your rule could work.
If you use this rule to figure out how much money Jawan made when he works 6 hours, it would be ((6•6)•9), which would then become 36•9. When you do out 36•9, you get how much money he earned, which was $324.