Mr Smith has a test bank of multiple choice questions. 15 questions are combinations, and 12 are permutations. Mr Smith is writing a test with 12 multiple choice questions.
a) How many different tests can he write if he wants to choose 7 combination and 5 permutation multiple choice questions.
b) After he has chosen the 12 questions, In how many orders can she put them on the test?
a) This should be pretty straightforward -there are 15C7 * 12C5 ways to choose 12 questions, order irrelevant.
b) Assuming the 12 questions are distinct, 12!.
a) so he can choose 7 out of the 15 combination questions and 5 out of the 12 permutation questions.
1514131211109 + 12111098 = answer
THIS IS WRONG ^ @MITer94 is right sorry haha 
b) _ _ _ _ _ _ _ _ _ _ _ _
12 11 10 9 8 7 6 5 4 3 2 1 <-- number of questions for each problem. For the 1st question, he has 12 choices, and for the 2nd question, he only has 11, bc one question has been used for the 1st question.
so 12! is your answer
at least… I think that’s how you do it…? numbers seem a bit big for a regular test problem though
@chubii for a), I’m pretty sure the order of which you select your permutations questions doesn’t matter. Weird since we’re sort of talking about permutations/combinations.
However I usually don’t like throwing around the word “permutation” a lot since a permutation is usually defined as a rearrangement of elements in a finite set.
oh you’re right for a)
no yeah, I had to re read your question since the questions Mr. Smith used were computation and permutation questions (but it ended up being unrelated)