Question

Find the sum of first 16 terms of the AP: 10, 6, 2…..
​

Answer 1

Hey mate here is your answer,

Sum of first 16 terms of An Ap is = 8

Answer 2

EXPLANATION.

A.P is 10,6,2,,,,,,,,,,,

As we know that,

First term of an ap = a = 10.

Common difference of an ap = d = b - a = c - b.

6 - 10 = 2 - 6.

-4.

Common difference = d = -4.

Formula of Sum of nth term of an ap.

⇒ Sₙ = n/2[2a + (n - 1)d].

⇒ S₁₈ = 18/2 [2(10) + (18 - 1)(-4)].

⇒ S₁₈ = 9[20 + 17(-4)].

⇒ S₁₈ = 9[20 - 68].

⇒ S₁₈ = 9[-48].

⇒ S₁₈ = -432.

                                                                                                                       

MORE INFORMATION.

Supposition of terms in A.P.

(1) = Three terms as : a - d, a, a + d.

(2) = Five terms as : a - 2d, a - d, a, a + d, a + 2d.

(3) = Four terms as : a - 3d, a - d, a + d, a + 3d.