The question #1 is not clear as to what is meant by "some order". Does "some order" mean sequential, but not necessarily consecutive? Does it mean that the common difference for the arithmetic progression can be zero or negative?

A possible solution for #1 and #2 is:
1. 20, 30, 40, 50, 60, 70, 80, 90
2. 30, 40, 50, 60, 70, 80, 90

Edited on February 2, 2013, 11:46 pm

Posted by Dej Mar on 2013-02-02 23:40:27