From a collection of 50 store customers, 2 are to be chosen to receive a special gift.
How many groups of 2 customers are possible?
This is a combination problem since the order of selection doesn't matter.
Recall that the combination formula is given by
[tex]{{{n\choose r}}}=\frac{n!}{r!(n-r)!}[/tex]Where n is the total number of subjects and r is the number of subjects to be choosen from n.
For the given case,
n = 50
r = 2
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