Ineed to know what mathematical operation applies to problem: tricia manages the front office at a local doctor's office and needs to figure out payroll for the front office clerk that is paid hourly. tricia also has to make sure that she keeps the front office clerk under 40 hours a week to avoid overtime pay. the front office clerks time sheet reads as follows :
monday tuesday wednesday thursday friday
480 minutes 450min. 495 min. 480 min. 300min.
monday tuesday wednesday thursday friday
480 min. 480 min. 480 min. 480 min. 480 min.

show what i need to do.

                        Week 1        Week 2
Monday               480             480
Tuesday              450             480
Wednesday        495             480
Thursday             480             480
Friday                   300             480
Total (minutes) 2205           2400

Week 1: 2205 mins / 60 mins = 36.75 hours
Week 2: 2400 mins / 60 mins = 40 hours

Add up all the minutes in a week. 
Divide the sum by 60 minutes to get the total hours worked for the week. 
Both weeks, the front office clerk did not exceed the 40 hours maximum. 
There will be no overtime pay.