Sequence And Series Question 391

Question: The value of $ \sum\limits_{n=1}^{10}{\sum\limits_{m=1}^{10}{(m^{2}+n^{2})}} $ equals

Options:

A) 4235

B) 5050

C) 7700

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

[c] $ \sum\limits_{n=1}^{10}{\sum\limits_{m=1}^{10}{(m^{2}+n^{2})}} $ $ =\sum\limits_{n=1}^{10}{[(1^{2}+n^{2})+(2^{2}+n^{2})+….+(10^{2}+n^{2})]} $ $ =10[{{(1)}^{2}}+{{(2)}^{2}}+….+{{(10)}^{2}}]+10[{{(1)}^{2}} $ $ +{{(2)}^{2}}+….+{{(10)}^{2}}] $ $ =\frac{20.10.11.21}{6}=7700 $