On Monday, Richard worked for 4 hours and earned $36. On Tuesday, Richard worked for 6 hours and earned $54. On Wednesday, Richard worked for 5 hours and earned $45. what is the rate of his earnings? Represent his earnings in a y=mx function, where hours are represented by y, and m represents the rate of change. If richard worked for 7 hours, how much money would he earn? How many hours did richard work on friday, when he earned $81