You can answer any 10 questions from a total of 12 questions on an exam. In how many different ways can you select the questions?
Because order doesn't matter in this problem, we use the combination formula.
We are picking
#color(white)("two")_nC_r = (n!)/((n - r)!r!) = (12!)/((12 - 10)!10!) = 66#
Hence, there are
Hopefully this helps!