C(5,2)乘以C(12,1)除以C(30,5)等于多少
问题描述：
C(5,2)乘以C(12,1)除以C(30,5)等于多少
组合.
答
C(m,n)=n!×(m-n)!/m!
C(5,2)×C(12,1)÷C(30,5)
=[2!×(5-2)!/5!]×[1!×(12-1)!/12!]÷[5!×(30-5)!/30!]
=(2×6×26×27×28×29×30)/(120×120×12)
=1187.55