Question:medium
Sum of the series \( 1(1) + 2(1+3) + 3(1+3+5) + 4(1+3+5+7) + \cdots + 10(1+3+5+7+\cdots+19) \) is equal to:
Sum of the series \( 1(1) + 2(1+3) + 3(1+3+5) + 4(1+3+5+7) + \cdots + 10(1+3+5+7+\cdots+19) \) is equal to:
Show Hint
To quickly square a number ending in 5 (like 55):
1. Multiply the first digit (5) by the next integer (6) to get 30.
2. Append 25 at the end.
Result: 3025.
Updated On: May 2, 2026
- \( 385 \)
- \( 1025 \)
- \( 1125 \)
- \( 2025 \)
- \( 3025 \)
Show Solution
The Correct Option is
Solution and Explanation
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