Find the sum of terms of the A.P. : 4, 9, 14, ......, 89.

Question

KnowledgeBoat · Accepted Answer

Let there be n terms in the above series. From above series, a_n = 89, a = 4 and d = 5. By formula, ⇒ a_n = a + (n - 1)d ⇒ 89 = 4 + 5(n - 1) ⇒ 85 = 5(n - 1) ⇒ 17 = n - 1 ⇒ n = 18. By formula, Sum of A.P. = Substituting values we get, Hence, sum of A.P. = 837.

Mathematics

Find the sum of terms of the A.P. : 4, 9, 14, ……, 89.

AP GP

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