Find the sum of first 15 multiples of 8.

Question

KnowledgeBoat · Accepted Answer

We need to find 8 + 16 + 24 + ..... + (15th term) The above series forms an A.P. with a = 8 and d = 8. By formula S_n = ⇒ S₁₅ = ⇒ 2S₁₅ = 15[16 + 14(8)] ⇒ 2S₁₅ = 15[128] ⇒ 2S₁₅ = 1920 ⇒ S₁₅ = 960 Hence, the sum of first 15 terms is 960.

Mathematics

Find the sum of first 15 multiples of 8.

AP GP

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Mathematics

Find the sum of first 15 multiples of 8.

AP GP

Related Questions

If Sn denotes the sum of first n terms of an A.P., prove that S30 = 3(S20 - S10).

Find the sum of first positive 1000 integers.

Find the sum of all two digit natural numbers which are divisible by 4.

Find the sum of all natural numbers between 100 and 200 which are divisible by 4.

If S_n denotes the sum of first n terms of an A.P., prove that S₃₀ = 3(S₂₀ - S₁₀).