How many terms of the AP : 9, 17, 25,....... must be taken to give a sum of 636?

Given, A.P. : 9, 17, 25,....... First term (a) = 9 and common difference (d) = 17 - 9 = 8. Let sum of n terms of the above A.P. be 636. ∴ S n = 636 By formula, S n = Substituting values we get : Comparing equation, 4n 2 + 5n - 636 = 0 with ax 2 + bx + c = 0, we get : a = 4, b = 5 and c = -636. By formula, n = Substituting values we get : Since, no. of term cannot be negative. ∴ n = 12. Hence, sum of 12 terms of A.P. = 636.

In an A.P., given a = 3, n = 8, S = 192, find d.

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In an A.P., given l = 28, S = 144, and there are total 9 terms. Find a.

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The first term of an AP is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.

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The first and the last terms of an AP are 17 and 350 respectively. If the common difference is 9, how many terms are there and what is their sum?

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Mathematics

How many terms of the AP : 9, 17, 25,……. must be taken to give a sum of 636?

AP

Related Questions

In an A.P., given a = 3, n = 8, S = 192, find d.

In an A.P., given l = 28, S = 144, and there are total 9 terms. Find a.

The first term of an AP is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.

The first and the last terms of an AP are 17 and 350 respectively. If the common difference is 9, how many terms are there and what is their sum?