# Combinatorics

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• Jan 24th 2008, 09:43 PM
cu4mail
Combinatorics
Can I hv help on solving this?

a) In a mathematics class with 30 students, the teacher wants 2 different students to present the solutions to problems 3 & 5 on the board. In how many ways can the teacher assign the problems?

b) Find the number of ways in which a team of 6 bats-men, 4 bowlers and a wicket- keeper may be selected from a squad of 8 bats-men, 6 bowlers and 2 wicket-keepers.

Thnx
• Jan 25th 2008, 12:34 PM
Jhevon
Quote:

Originally Posted by cu4mail
Can I hv help on solving this?

a) In a mathematics class with 30 students, the teacher wants 2 different students to present the solutions to problems 3 & 5 on the board. In how many ways can the teacher assign the problems?

\$\displaystyle {30 \choose 2}\$

Quote:

b) Find the number of ways in which a team of 6 bats-men, 4 bowlers and a wicket- keeper may be selected from a squad of 8 bats-men, 6 bowlers and 2 wicket-keepers.
\$\displaystyle {8 \choose 6} {6 \choose 4} {2 \choose 1}\$

why is that?
• Jan 26th 2008, 02:58 AM
cu4mail
Thanks
Quote:

Originally Posted by Jhevon
\$\displaystyle {30 \choose 2}\$

\$\displaystyle {8 \choose 6} {6 \choose 4} {2 \choose 1}\$

why is that?

Thanks for your help.