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Q

permutation and combination

5p3 answer given - 5*4*3 =60 My question is why 3 is also taken here . I think the answer should be 20 because 5*4*3/3*2*1
A

5P3 is an example of nCr which is DEFINED as n! / (n-r)!

In this case, 5! / 2! has the 5•4•3 expansion…it’s 5! but with the 2•1 having cancelled the last two factors of 5!

Answer 60 is entirely correct.

2 months ago
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