A class contains 10 violinists, 6 guitarists and 5 pianists. A group of 7 consisting of 4 violinists, 2 guitarists and 1 pianist is chosen.

(a) In how many ways can this group be chosen? [2]

On another occasion a group of 5 is chosen. It must contain at least 2 violinists, at least 1 guitarist and at most 1 pianist.

(b) In how many ways can the group of 5 be chosen? [4]