During the weekdays, Paris studies 3 hours a day for 5*3 = <<3*5=15>>15 hours
She studies 4 hours on Saturday and 5 hours on Sunday for a total of 4+5 = <<4+5=9>>9 hours on the weekends
If she studies 15 hours during the weekdays and 9 hours on the weekends then she studies 15+9 = <<15+9=24>>24 hours per week
There are 15 weeks in the fall semester and she studies 24 hours a week so she will spend 15*24 = <<15*24=360>>360 hours studying
#### 360