SOLUTION: You are allowed to omit two out of 12 questions on a quiz. How many ways can you select the questions to omit? Can you please show the break down of the work so I can figure out th

Algebra ->  Permutations -> SOLUTION: You are allowed to omit two out of 12 questions on a quiz. How many ways can you select the questions to omit? Can you please show the break down of the work so I can figure out th      Log On


   

Question 590510: You are allowed to omit two out of 12 questions on a quiz. How many ways can you select the questions to omit? Can you please show the break down of the work so I can figure out the formula
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
there are 12C2 ways of selecting two things from a group of twelve

there are 12 ways to select the 1st question and then 11 ways to select the 2nd question
___ BUT ___ selecting question 5 and then 8 is the same as selecting 8 and then 5 (same two questions are omitted)

so the number of ways is ___ (12 * 11) / 2 (which is 12C2)