Question

sum of first 10 terms of AP 3, 11, 19 is

Answer 1

Here, a=3, d=11-3=8

S₁₀ = 10/2 [2 x 3 + 9 x 8] = 5 [6+72] = 5 x 78 = 390

Answer 2

Given:a=3

d=11-3=8

Sum=10/2(2(3)+9(8))

=5*78

=390