Probability problems (I think these might be permutations and combinations)

1. A lift in a building can carry a maximum of 12 passengers. 19 people are waiting for the lift. In how many ways can the passengers be carried in two journeys?

2. How many groups of 4 letters can be formed from the letters Y, S, L, K, I, if the second letter chosen must always be I? (Letters cannot be repeated.)

3. Five chocolates are selected at random from a box. In the box there are 5 strawberry creams, 7 orange chip, 7 toffee choc and 8 nut crunch.

a) How many different combinations of five chocolates can be chosen?

b)Tara would like 2 orange chip, 2 toffee choc and 1 strawberry cream. What is the probability she chooses this selection?