First slide

Binomial theorem for positive integral Index

Question

If the coefficient of $(3 r + 4) t h$ term and $(2 r - 2) t h$ term in the expansion of ${(1 + x)}^{20}$ are equal then $r$ is equal to :

Moderate

A

4
B

5
C

7
D

8

Solution

$^{20} C_{3 r + 3} =^{20} C_{2 r - 3} \Rightarrow (3 r + 3) + (2 r - 3) = 20 \Rightarrow r = 4$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App