Question

38) Find the sum of the terms from 10th term to 20th term of AP 3,7,11,15.​

Answer 1

Answer:

Explanation:The answer is very simple

Hope, you understood the answer

Answer 2

Step-by-step explanation:

a = 3

d = 7 -3 = 4

S20 = 20/2 [ 2(3) + ( 20 -1) (4) ]

= 10 [ 6 + 76]

= 820

Now,

S10 = 10/2 [2(3) + ( 10-1 ) (4)]

= 5 [ 6 + 36 ]

= 5 × 42

= 210

Required sum = S20 - S10

= 820 - 210

= 610