clearing up

hey .. i need a little help ... remebering stratified samling for this question ....a youth club has 120 members of whom 45 are girls and 75 are boys . the leader would like to change the evening on which the meet and he decides to seek the views of the members on this proposed change

a) state what is meant by a census in this context
b) one advantage and one disadvantage of using a sample compared with a census
c) he decides to use a stratified sample of 24 members . the 2 strata being the girls and boys who are members of the club determine the numbers of girls and boys in the sample.. honestly i can't remember anything on sampling i haven't done it this year .. help would be much appreciated !!! thank

i don't know what a census is .. i might've heard of it once but that's it ... / for b) .. i'm no sure but for c ) .. i've learnt how to do it .. just can't remember properly ... is it ... (45/120) x 24 or x 100 and the the same for 75 .. if it's x 100 what do i do with the 24?? the more i wright questions on here the more i realize how much help i really need :\ lol