[tex]a) \: 4 \times 3 \times 2 \times 1 = 24 \: ways[/tex]
[tex]b) \: this \: one \: is \: a \: little \: more \: \\ complex \: so \: bear \: with \: me \\ poss \: 1 = all \: \: tie \: for \: first \\ poss \: 2 = 3 \: tie \: for \: second \\ poss \: 3 = 2 \: tie \: for \: third \\ poss \: 4 = no \: one \: ties[/tex]
They can all tie for first place in one way,
which is, that they all arrive first with no order.
If one person arrives in first place, this leaves 3 to tie for second, All 4 players can arrive first and the other 3 would have to tie in second so,
If two people take the first two spots, this leaves two people to tie for third place, All four players can occupy the first position and the other 3 can switch in second leaving two to tie at last. and this can happen in 4 ways.