Question

The number of terms in the expansion of $(a+b+c{)}^{20}$ is

• A. $231$
• B. $226$
• C. $321$
• D. $326$

Answer 1

The correct option is A $231$

Given expansion $(a+b+c{)}^{20}$
The number of terms in the expansion
$={}^{n+3-1}{C}_{3-1}={}^{20+3-1}{C}_2={}^{22}{C}_2=\frac{22\times 21}{2}=11\times 21=231$