The formula to obtain Binomial Coefficient can be written as: n! / r! × ( n - r )! , which is equal to the number of combinations. Here, n -> number of unique objects r -> number of objects that are considered ( r <= n ) ____________________ Suppose n = 4 Objects that are being considered: ( 1 ) A ( 2 ) B ( 3 ) C ( 4 ) D _____________________ Let us restrict ourselves to deal with only three objects at a time. We will attempt to form combinations taking only three objects at a time. So, here r = 3 _____________________ From the ongoing discussion, n = 4 and r = 3 So, No. of combinations = 4! / ( 3! × ( 4 - 3 )! ) = 4 Let us observe the four combinations that are formed: ________________________...