Find the sum of a 24–term arithmetic sequence where the first term is 12 and the last term is 219

Harrison Mills

Harrison Mills

Answered question

2022-09-23

Find the sum of a 24–term arithmetic sequence where the first term is 12 and the last term is 219

Answer & Explanation

ruinsraidy4

ruinsraidy4

Beginner2022-09-24Added 17 answers

What you are actually doing (in your mind or on paper) is putting the sequence in a row and beneath that you put the same sequence in reverse order. Now when you add them vertically, two by two, you will get the same number (=first+last) every time:
Example :
1 2 3 4 5
5 4 3 2 1 +
6 6 6 6 6
This will be 6 x 5 = 30, because there are 5 terms here. But now you have added two sequences, so you have to divide by 2.

In your case: S u m = ( 12 + 219 ) 24 2

Do you have a similar question?

Recalculate according to your conditions!

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?