# HELPPP ...... Impossible... PLZ

• March 5th 2008, 11:07 PM
wikji
HELPPP ...... Impossible... PLZ
480 girls and 420 guys make up a school...
How many committees of 5 Can i make if at least 1 guy must be on each committee.

Answere is 8 042 346 130 104
• March 5th 2008, 11:13 PM
mr fantastic
Quote:

Originally Posted by wikji
480 girls and 420 guys make up a school...
How many committees of 5 Can i make if at least 1 guy must be on each committee.

Answere is 8 042 346 130 104

I was tempted not to reply ...... After all, no point trying to answer an impossible question .......

No restriction on who is on committee: ${900 \choose 5}$.

Restriction - No guy on committee (all girls): ${480 \choose 5}$.

Therefore .....

Restriction - at least one guy on committe: .......
• March 6th 2008, 02:52 AM
wikji
[QUOTE=mr fantastic;113682]I was tempted not to reply ...... After all, no point trying to answer an impossible question .......

No restriction on who is on committee: ${900 \choose 5}$.

Restriction - No guy on committee (all girls): ${480 \choose 5}$.

Therefore .....

Restriction - at least one guy on committe: ......Show me how to get it ...
• March 8th 2008, 02:34 AM
mr fantastic
[QUOTE=wikji;113711]
Quote:

Originally Posted by mr fantastic
I was tempted not to reply ...... After all, no point trying to answer an impossible question .......

No restriction on who is on committee: ${900 \choose 5}$.

Restriction - No guy on committee (all girls): ${480 \choose 5}$.

Therefore .....

Restriction - at least one guy on committe: ......Show me how to get it ...

(The words in red are the response to my reply).

You have been shown. What do you think 'no guy on committe' plus 'at least one guy on committe' adds up to ..... Some attempt to understand a push in the right direction goes a long way.

And some manners go a long way, too. Please, thankyou etc.