Question

Find the sum of 12th terms of two A.P 2, 4, 6, 8... and 3, 6, 9, 12 ....​

Answer 1

Answer:

AP¹ : 2,4,6,8...

a = 2 & d = 2

Sⁿ = n/2[ a + (n-1)d ]

S¹² = 12/2[ 2 + 11×2]

S¹² = 144

AP² : 3,6,9,12...

a = 3 & d = 3

S¹² = 12/2[ 3 + 11×3]

S¹² = 216

S¹² of AP¹ = 144

S¹² of AP² = 216

Hope this helps you!