The first term of an arithmetic series is 16 and the last is 60. The sum of an arithmetic series is 342. find the common difference.
I can't work out n. Please help.
Hello, greghunter!
You're expected to know this formula:
. .
We have: .The first term of an arithmetic series is 16 and the last is 60.
The sum of the arithmetic series is 342. .Find the common difference.
Then: .
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
If you didn't know that formula, you can still work it out.
First term: . .[1]
Last term: . .[2]
Sum of the first n terms: . .[3]
Substitute [1] and [2] into [3]: .
. . . . . See?