Combinations

A box contains 5 color pencils. How many different sets of 3 pencils can be chosen from it?

Find the number of ways of selecting 2 vowels and 2 consonants from the letters of the set {I, N, T, E, R, V, A, L}.

How many 4 card hands that contain exactly 3 aces and 1 queen can be chosen from a 52 card deck?

If nC2=28, then what is the value of n?

How many different 2 digit numbers can be formed using {2, 3, 4, 5, 6, 7, 8}, if repetition of a digit is not allowed?

How many different 2 number sets can be formed using {2, 3, 4, 5, 6, 7, 8}, if repetition of a digit is not allowed?

How many different teams of 8 can be chosen from 12 players?

In a box there are 7 pens and 10 pencils. How many ways can 4 pens be chosen from the box?

In a group of 20 members, 12 are boys and 8 are girls. Find the number of ways of forming a 15 member committee which should include 9 boys.