Alrighty, so I'm working through some pre-test questions and I ran across two which have really stumped me.
- If you have a team that enters a best out of 7 series, how many different ways can you win in exactly 6 games.
- I originally though this question could be done by taking 7!/(6!)(1!) where 7=n, 6=wins, and 1=losses, to give an answer of 7, but I was wrong. Could I just use nPr to get 5040, or would that be wrong too?
- If a baseball team is made up of 7 girls and 8 boys and there are 9 people on the field at one time (at least 4 of which must be girls) then how many different ways could you arrange a team?
- In this question I used the nCr formula then went girlsCr times boysCr to get 1960, but this was wrong. I asked my teacher and he said that I missed out on the fact that there could be more then 4 girls on the field. This lead me to more confusion but I believe that by adding on a regressive scale (as done above) I could go (7C4 x 8C5) + (7C5 x 8C4) + (7C6 x 8C3) + (7C7 x 8C2)=3850 combinations. This seems to make sense because the more girls added to the field the fewer options for arrangement. Nevertheless I'm still unsure and would be grateful for any help.
Last edited: