Question

for an ap 8, 16 ,24 ,......,120. based on solutions of above question. find the value of sum of first ten terms​

Answer 1

Answer:

S₁₀= 440

Step-by-step explanation:

Given A.P , 8,16,24,.......,120

find sum of first 10 terms, S₁₀

sum of n terms is given by Sₙ = n/2 (a+l) , where

                                                    n is the no. of terms,

                                                    a is the first term &

                                                    l is the last term

if we want to find the 10th term, by formula tₙ = a + (n-1)d

t₁₀ = 8 + (10-1) 8 = 8+9(8) = 8+72 =80 (which is also 'l')

∴ S₁₀ = 10/2 (8+80) = 5(88) = 440