Question

I am doing my math home work and it is on factorials and combinations and I thought I understood it but now I am confused. My question was Evaluate 6C3. So I wrote out 6*5*4*3*2*1, then 6*5*4*3*2*1*3*2*1. I cancelled out common factors,6,5,4,3,2,1. Leaving me with 3*2*1=6 but 6 was wrong. HELP

Answer 1

\[_{6}C _{3}=\frac{ 6*5*4 }{3*2*1 }\]

Answer 2

nCr simplifies to (nPr)/r!

Answer 3

is it 20

Answer 4

it is 20