Question

find the value of n if c(12,7) - c(11,6) = c(n,7)​

Answer 1

Given

35

C

n+7

=

35

C

4n−2

It is in form if

n

C

x

=

n

C

v

, then

x=y or x+y=n

now

(i)

n+7=4n-2

4n-n=7+2

3n=9

n=3

(ii)

n+7+4n-2=35

5n+5=35

5n=30

n=6