Question 1163374:  Every year, students have to decide which four classes to take each semester. They must take two core classes each semester consisting of Math, Science, English, or Social Studies. There are 6 electives to choose from for the remaining two classes. 
 
A student wants to take Orchestra, AP Calculus, Physics 1, and Debate. However, Orchestra is only offered 1st period or 2nd period, and AP Calculus is only offered 4th period. How many schedules would meet these criteria? (no math required. Use reasoning!) 
 Answer by Boreal(15235)      (Show Source): 
You can  put this solution on YOUR website! Four schedules 
For the second,  
OPDA 
or ODPA 
or PODA 
or DOPA 
4th period is fixed 
1st period has 3 possibilities  
once that is filled, if O then there are 2 ways to fill the schedule 
if not O, there are two ways to fill the schedule 
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