For an A.P. the sum of its terms is 60, common difference is 2 and last term is 18. Find the number of terms in the A.P.
AP GP
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For an A.P. the sum of its terms is 60, common difference is 2 and last term is 18. Find the number of terms in the A.P.

KnowledgeBoat · Accepted Answer

Given, Common difference (d) = 2 Last term (l) = 18 Let no. of terms be n. ⇒ l = a + (n - 1)d ⇒ 18 = a + 2(n - 1) ⇒ 18 = a + 2n - 2 ⇒ a + 2n = 20 ⇒ a = 20 - 2n .........(1) By formula, S_n = Substituting values we get : Substituting value of a in above equation, we get : Hence, no. of terms = 4 or 15.

Mathematics

For an A.P. the sum of its terms is 60, common difference is 2 and last term is 18. Find the number of terms in the A.P.

AP GP

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Mathematics

For an A.P. the sum of its terms is 60, common difference is 2 and last term is 18. Find the number of terms in the A.P.

AP GP

Related Questions

If nth term of an A.P. is (2n - 1), find its 7th term.

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Find the geometric progression whose 5th term is 48 and 8th term is 384.

If n^th term of an A.P. is (2n - 1), find its 7^th term.

If the sum of first n terms of an A.P. is 3n² + 2n, find its r^th term.

Find the geometric progression whose 5^th term is 48 and 8^th term is 384.