This is my math problem using ncr method. 75x74x73x72x71 divided by 5x4x3x2x1 what does that equal
You must make sure not to confuse the two:
Combinations[nCr]=n! / [(n-r)!.r!]. Example:75C5=75! / [(75-5)!.5!]=17,259,390.
Permutations[nPr] =n! / [n-r]!. Example:75P5=75! / [75-5]! =2,071,126,800.
\(\quad \frac{75\times 74\times73\times72\times71}{5\times4\times3\times2\times1}\\ = \frac{75}{5\times3}\times\frac{72}{4\times2}\times73\times71\times74\\ = 5\times9\times73\times71\times74\\=17259390\)
