You have two jobs. One job pays nine dollars per hour and the other job pays $7.50 per hour. You worked 18 hours last week and earned $145.50. How many hours did you work at each job?

And then we conclude that for the first job he works 7 hours and for the second job 11 hours

Step-by-step explanation:

We can define the following notation:

represent the number of hours worked for one job

represent the number of hours worked for the other job

represent the hourly payment for the first job

represent the hourly payment for the other job

And we can define the following equations:

  (1) represent the toal number of hours worked

 (2) represent the total amount earned

From equation (1) if we solve for X we got:

(3)

Replacing equation (3) into equation (2) we got:

And after solve the equation we can find the value of Y:

And solving for X from equation (3) we got:

And then we conclude that for the first job he works 7 hours and for the second job 11 hours