Question:medium
Sum of first and 25th terms of an arithmetic sequence is 70.
(iii) Find the sum of first 25 terms of this sequence.
Sum of first and 25th terms of an arithmetic sequence is 70.
(iii) Find the sum of first 25 terms of this sequence.
(iii) Find the sum of first 25 terms of this sequence.
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When you know the first and the last term of the sum you want to compute, always use the formula Sₙ = (n)/(2)(first term + last term). It's the most efficient method and avoids the need to find a and d separately.
Updated On: Mar 16, 2026
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