Question

the algebraic sum of first termof anAP is 2n+8n how many consecutive term of the sequence starting from first are to be added to get 330

Answer 1

Answer:

11

Step-by-step explanation:

Sn = 2n2 + 8n (Given) 330 = 2n2 + 8n 2n2 + 8n – 330 = 0 n2 + 4n – 165 = 0 n2 + 15n – 11n – 165 = 0 n(n + 15) – 11 (n + 15) = 0 (n + 15) (n – 11) = 0 If n + 15 = 0 ⇒ n = – 15 (terms are not negative) n – 11 = 0 ⇒ n = 11 ∴ Hence, total 11 term from starting to be added.