John works two jobs.

Question

John works two jobs. As a security guard he earns 9.75 per hour. As a landscaper he earns $15.00 per hour. One week John worked a total of 40 hours and earned $468.75. How many hours did he work at each job?

Answer 1

Easier to use substitution method rather than elimination.

S + L = 40 so L = 40 - S

9.75S + 15L = 468.75

9.75S + 15(40 - S) = 468.75

9.75S + 600 - 15S = 468.75

-5.25S = -131.25

S = 25 hrs; L = 15 hrs.

Answer 2

9.75S + 15L = 468.75

S+L = 40

9.76S + 9.75L = 40(9.75) = 390

subtract last equation from 1st

15L-9.75L = 468.75-390

5.25L = 78.75

L = 78.75/5.25 = 15 hours landscaping

S = 40-15 = 25 hours security guarding