Question

iThe fourth term of an AP is 10 and the eleventh
term of it exceeds three times the fourth term
by I. Find the sum of the first Find the Sum
of the first 20 terms of the A-P.​

Answer 1

Answer:

Step-by-step explanation:let the first term be a

And the common difference is d

Then 4th term is =a+3d=10.........(i)

And 11th term is =a+10d=30.........(ii)

Now ii-i gives

d=20/7 and a=10/7

So as we know that sum of 1st 20 terms is ;n/2{2a+(n-1)d}

=10x{20/7+19x20/7}

=4000/7

=571.42

Hope this answer helps you

Answer 2

Step-by-step explanation:

4th term is a+3=10

11th term is =a+10d=30