C-13-Q071mediumsingle_mcq82+92+102+⋯+152=?8^{2} + 9^{2} + 10^{2} + \cdots + 15^{2} = ?82+92+102+⋯+152=?a110011001100b124012401240c138013801380d980980980ব্যাখ্যাThis equals ∑115k2−∑17k2=15×16×316−7×8×156=1240−140=1100\sum_{1}^{15}k^2-\sum_{1}^{7}k^2=\frac{15\times16\times31}{6}-\frac{7\times8\times15}{6}=1240-140=1100∑115k2−∑17k2=615×16×31−67×8×15=1240−140=1100.