Question

The sum of the first and 19th terms of an arithmetic sequence is 60. The sum of its

first and 20th terms is 62.

a) What is its common difference.

b) What is the sum of its 8th and 12th terms.

c) Find its 10th term​

Answer 1

Answer:

To find the sum for arithmetic sequence, sn= n(n+1)/2, it is shown (n+1)/2, can be replaced with the average of nth term and first term.