Can I hv help on solving this?

a) In a mathematics class with 30 students, the teacher wants 2 different students to present the solutions to problems 3 & 5 on the board. In how many ways can the teacher assign the problems?

b) Find the number of ways in which a team of 6 bats-men, 4 bowlers and a wicket- keeper may be selected from a squad of 8 bats-men, 6 bowlers and 2 wicket-keepers.

Thnx