More generally, the formula for finding the number of combinations of k objects you can choose from a set of n objects is:

n!

n_C_k = ---------------

k! (n - k)!

Combinations & Permutations Programs

The Algorithm For N-Choose-R in High Level Pseudocode:

Let k = min (r, n-r)

Start answer = 1

Start multiplier = n

Start divisor = 1

while divisor<= k do

{ answer = ( answer * multiplier ) div divisor # this will evenly divide

decrement the multiplier

increment the divisor

}

n!

n_C_k = ---------------

k! (n - k)!

Combinations & Permutations Programs

The Algorithm For N-Choose-R in High Level Pseudocode:

Let k = min (r, n-r)

Start answer = 1

Start multiplier = n

Start divisor = 1

while divisor<= k do

{ answer = ( answer * multiplier ) div divisor # this will evenly divide

decrement the multiplier

increment the divisor

}

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