5) Mario owns a plumbing business. He charges an hourly rate plus a onetime set up fee. His first job was 4 hours and he charged $450. His second job was 3 hours and he charged $675. If his set up fee is $150, how much does he charge per hour?

Results are below.

Step-by-step explanation:

First, we need to calculate the variable income per job:

First job= 450 - 150= 300

Second job= 675 - 150= 525

Now, the hourly rate:

Hourly rate= total variable income / number of hours

First job= 300 / 4= $75

Second job= 525 / 3= $175

It is probably that the second job was 7 hours long. If not, he doesn't charge the same amount per hour