Binomial Theorem And Its Simple Applications Question 154
Question: If the coefficient of $ {{(2r+4)}^{th}} $ and $ {{(r-2)}^{th}} $ terms in the expansion of $ {{(1+x)}^{18}} $ are equal, then r=
[MP PET 1997; Pb. CET 2001]
Options:
A) 12
B) 10
C) 8
D) 6
Show Answer
Answer:
Correct Answer: D
Solution:
- $ ^{18}{C_{2r+3}}{{=}^{18}}{C_{r-3}},\Rightarrow 2r+3+r-3=18\Rightarrow r=6 $
BETA
