Answer:
1260 hours
Step-by-step explanation:
Depending on your location, different states have different school hours and holidays. However, lets just assume it's the average. The average high school has 180 days of school each year with 7 hour school days.
180(7) = 1260 hours
Of course, this does not account for time spent at home studying, doing homework, tutoring, or other things of the sort.