Question

If the value of $1 + 2 + 3 + ..........+n$ is $55,$ then the value of $1^3 + 2^3 + 3^3 + ..........+ n^3$ is

• A. 165
• B. 385
• C. 3025
• D. 555

Answer 1

Answer: (C)

3025

Answer 2

$1^{3}+2^{3}+.....+n^{3} = \Sigma n^{3}$ $= \left(\Sigma n\right)^{2}$ $=(55)^{2}$ $=3025$ $\left[\because \sum n=55\right]$