Just having a bit of a problem with a particular permutation question.
Q - Four girls (Anne, Pela, Jeanette and Philippa) and three boys (Tony , Jason, and Bill) arrange themselves in a line at the checkout. If the arrangements are random, find the probability that Anne and Pela will be served before tony
5 possible situations, two girls always on the right side of the line, tony always on the left side of the line.
x x x x x | x x permutations 5P5 * 2!
x x x x | x x x permutations 5P4 * 3!
x x x | x x x x permutations 5P3 * 4!
x x | x x x x x permutations 5P2 * 5!
x | x x x x x x permutations 5P1 * 6!
add them up and put it over 7! and it comes out as 5/3 obviously wrong lol :S.