A school's student council has 12 eligible members: 7 boys and 5 girls. The council needs to select delegations of various sizes and compositions for different events throughout the year, and wants to know exactly how many distinct delegations are possible in each case.
Separately, the council also needs to arrange 5 distinct trophies in a row on a shelf for the annual awards ceremony, and wants to know how many different arrangements are possible, as well as how many ways a first-place and second-place trophy could be selected and displayed in order on a smaller stand.
Separately again, for a puzzle at the same ceremony, the council wants to know how many distinct codes of different lengths can be formed using the five distinct letters of the word "LEADS", with no letter repeated in any single code.