Find the 91st term of the arithmetic sequence 28, 8, - 12, ... 28,8,-12, ...

Since there are only three terms and they repeat we can easily figure this out.

To do that all we have to do is determine how far away 91 is from a multiple of three. If it lands on a multiple of three it will be - 12. If it is two above a multiple of three it will be eight. If it is one above a multiple of three it will be 28.

So the 91st term in one above a multiple of three the answer will be 28.