Question

nth term of ap is 3n-1 find the sum of 10th term to 20th term​

Answer 1

Step-by-step explanation:

nth term = 3n - 1

10th term = 3*10 - 1 = 29

20th term = 3*20 - 1 = 59

Now, we have to find the sum of :- 10th term to 20th term

So ,

• First term, a = 29
• Last term, l = 59
• Number of term, n = 10

Sum of AP = (a + l) n/2

= (29 + 59)*10/2

= 88*5

= 440