MCQ
${11^3} + {12^3} + .... + {20^3}$
- AIs divisible by $5$
- ✓Is an odd integer divisible by $5$
- CIs an even integer which is not divisible by $5$
- DIs an odd integer which is not divisible by $5$
✓
Answer
Correct option: B.
Is an odd integer divisible by $5$
b
(b) $\sum\limits_{n = 1}^{20} {({n^3})} - \sum\limits_{n = 1}^{10} {({n^3})} $
(b) $\sum\limits_{n = 1}^{20} {({n^3})} - \sum\limits_{n = 1}^{10} {({n^3})} $
$= \left[ {\frac{{n(n + 1)}}{2}} \right]_{n = 20}^2 - \left[ {\frac{{n(n + 1)}}{2}} \right]_{n = 10}^2$
$= 44100 -3025 = 41075.$
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