Question

find the value of n 20C n+2 = 20C 2n-1​

Answer 1

Answer:

20

C

n−2

=

20

C

n+2

⇒

20

C

n−2

=

20

C

20−n−2

(∵

n

C

r

=

n

C

n−r

)

⇒

20

C

n−2

=

20

C

18−n

On comparing n−2=18−n

⇒n+n=18+2

⇒2n=20

⇒n=

2

20

=10

Hence, n=10

Explanation:

please give this answer brilliant

Answer 2

Explanation:

20

c

n-2

20 c

n+2

20 c

20-n-2

(:

n

c

r

n

c

n-r

)

20

c

n-2

20

c

18-n

on comparing n-2 answer 18-n

n+n answer 18+2

2n answer 20

n ans 2

20

ans 10

Hence , n ans 10