Friday, April 6, 2012
JCCDQBHWHCB007(i) Combinatorics : Choosing with special conditions
This sort of question has appeared in the GCE ‘A’ levels before. For questions with special conditions, a good approach is to consider to the special conditions first.
Suggested Approach and Solution:-
Number of ways to choose the young player = 2C1 = 2
The captain must be in, so two vacancies have been taken up and there are 3 left. These places must be filled from the 7 eligible other players (excluding the captain and the two youngest players). There are 7C3 = 35 ways to do this. The total number of ways is
35 x 2 = 70