Eric M. answered 11/08/19
Physician-Scientist (MD/PhD) With Experience in Biostatistics and R
There are 12 unique students, and you must pick three. This is a combinations problem. So that equals nCr(12,3) = 12!/(3!*(12-3)!) = 12!/(3!*9!) = 10*11*12/(3!) = 10*11*12/6 = 10*11*2 = 220. That's answer choice D.
Jim F.
thank you! What's the base formula for combinations problem?11/08/19