The total number of hours Vanessa work in a week is:
total work hours = (8 hours / day) * 5 day / week
total work hours = 40 hours per week
The total number of hours she did not work:
total hours did not work = (90 minutes)(1 hour / 60 minutes) + (45 minutes)(1 hour / 60 minutes) + 2.5 hours
total hours did not work = 4.75 hours
The amount of hours Vanessa work last week can be calculated using the formula:
work hours = total work hours - total hours did not work
work hours = 40 hours – 4.75 hours
work hours = 35.25 hours
