Question

if nc8 =nc2 ,find nc2​

Answer 1

Answer:

Given, nC8=nC2

nC2=2!(n−2)!n!

nCn−2=2!(n−(n−2))!(n−2)!=2!(n−2)!n!

⟹nC8=nC2=nCn−2

⇒n−2=8,⇒n=10

∴nC2=10C2=2!(10−2)!10!

=2!8!10!=2×1×8!10×9×8!=45