Question

1^2 +2^2 +3^2 +...+10^2 is equal to according to arthimetic progression ?
(a) 380 (b) 385 () 390 (d) 392​

Answer 1

Answer:

385

${1}^{2} + {2 }^{2} + {3}^{2} + ..... + {n }^{2} = \frac{n \times n + 1 \times 2n + 1}{6}$

here n=10 so put value of n in formula and get answer