MCQ
Find the sum of series 13 + 33 + 53 +…………………………..+ 113.
- A2556
- B5248
- C6589
- D9874
Solution:
13 + 33 + 53 +…………………………..+ 113
= (13 + 23 + 33 +……+ 113) – (23 + 43 + 63 + 83 + 103)
= (13 + 23 + 33+……113) – 23(13 + 23 + 33 + 43 + 53)
$\Big(\frac{11\times12}{2}\Big)^2-8\Big(\frac{5\times6}{2}\Big)^2$
$=66^2-8\times15^2$
$4356-1800=2556.$
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
The number of possible outcomes when a coin is tossed 6 times is.