A group of 8 friends want to play doubles tennis. How many different ways can the group be divided into 4 teams of 2 people?
A. 420
B. 2520
C. 168
D. 90
E. 105
I understood it was previously discussed in this forum. However I got problem with the other question which goes as follows:
There are 12 girls and 15 boys.In how many ways we can form 4 pairs of boys and 4 pairs of girls for a dance .
1 12C4*15c4
2 12C4*15C4*8
3 12C4*15C4*4!
4 27C4*4
[spoiler]I thought the ans to be one as we have already considered various combinations resulting from the question . If the order of the groups had not been important we would have divided by 4!. As the order is already considered in 1. why do we have to multiply by 4! over here.[/spoiler]
A. 420
B. 2520
C. 168
D. 90
E. 105
I understood it was previously discussed in this forum. However I got problem with the other question which goes as follows:
There are 12 girls and 15 boys.In how many ways we can form 4 pairs of boys and 4 pairs of girls for a dance .
1 12C4*15c4
2 12C4*15C4*8
3 12C4*15C4*4!
4 27C4*4
[spoiler]I thought the ans to be one as we have already considered various combinations resulting from the question . If the order of the groups had not been important we would have divided by 4!. As the order is already considered in 1. why do we have to multiply by 4! over here.[/spoiler]
Last edited by kaulnikhil on Sun Jun 28, 2009 10:47 am, edited 1 time in total.
