SOLUTION: Roy must elect 3 courses from among 3 courses in group I and 6 courses in group II. If he must take at least 1 of his 3 electives from each group, how many choices does he have?(Hi
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-> SOLUTION: Roy must elect 3 courses from among 3 courses in group I and 6 courses in group II. If he must take at least 1 of his 3 electives from each group, how many choices does he have?(Hi
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Question 1131671: Roy must elect 3 courses from among 3 courses in group I and 6 courses in group II. If he must take at least 1 of his 3 electives from each group, how many choices does he have?(Hint: First find how many choices he has if he elects only 1 course from group I. Then find how many choices he has if he elects 2 courses from group I. Since he must do one or the other of these, the final answer is the sum of the two answers.)
I think the answer is 36 Found 2 solutions by greenestamps, ikleyn:Answer by greenestamps(13200) (Show Source):
A straightforward application of "n choose r" and basic rules of counting.
Choose 1 of the 3 courses in group I AND 2 of the 6 courses in group II, OR choose 2 of the 3 courses in group I AND 1 of the 6 courses in group II:
If you aren't familiar with C(n,r) ("n choose r") then search the internet and learn about it. It is basic to many types of problems similar to this one.
