Question

The sum of the series :
$(2{)}^2+2(4{)}^2+3(6{)}^2+...$ upto 10 terms is :

• A. $11300$
• B. $11200$
• C. $12100$
• D. $12300$

Answer 1

Answer: (C)

$2^2+2{\left(4\right)}^2+3{\left(6\right)}^2+......upto10terms$
$=2^2\left[1^3+2^3+3^3+......upto10terms\right]$
$=4.{\left(\frac{10\times 11}{2}\right)}^2=12100$