What is the Number of Possible Committees with Frank Included?

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Homework Statement

A club for 18 members, among them Frank. They'll pick out a komitee of 5 members.
(a. How many different komitees is produced? Easy, just the binom. 18 over 5.)

b, How many if Franks in? (The question)

Homework Equations

(Unarranged sortments with no takebacks)
binominalkoefficient nCr:
( p )
( r )
((p over r))

The Attempt at a Solution

18 over 5 minus 17 over 5?? No.

 

[Sourabh N]

for b. if Frank is always in, you have to choose only 4 members among the remaining 17, which is C^{17}_{4}, equivalent to your 18 over 5 minus 17 over 5.

 

[pace]

ah, 17C4, thanks a bunch.