Question

nC2=nC3 then the value of nC4? ​

Answer 1

Answer:

Step-by-step explanation:

nC2 = n! / (n-2)! 2! = n(n-1) (n-2)! / (n-2)! 2! = n(n-1) / 2

nC3 = n! / (n-3)! 3! = n(n-1) (n-2) (n-3)! / (n-3)! 3!  = n(n-1) (n-2) / 6

n(n-1) (n-2) / 6 = n(n-1) / 2

(n-2) / 6 = 1/2

n-2 = 3

n = 5

nC4 = 5C4 = 5! / 4! 1! = 5

Answer 2

Answer:

The value of  nC4 = 5

Step-by-step explanation:

Given that nC3 = nC2  

We know that,

if nCx = nCy

then x + y = n or x = y

Here nC3=nC2

x=3 , y=2

3 + 2 = n  

∴ n = 5

By substituting the value of n

nC4 = 5C4 = 5!/(5-4)!4!

 ∴ The value of 5C4 = 5