In an AP the sum of first n terms is 3n^2/2+13n/2 Find the 25th term. – InterviewSolution

1.

In an AP the sum of first n terms is 3n^2/2+13n/2 Find the 25th term.

Answer»

N term sum = 3n²/2 + 13n/2as we know that nth term = (Sum of nth term ) -( sum of (n-1)th term)

so 25th term = (sum of 25terms) - ( sum of 24 terms) =(3×(25)²/2 +(13×25)/2) - ( 3×(24)²/2 + (13×24)/2) = 1100 - 1020 =80

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