Okay so there are four numbers represented by A,B,C,D. Their sums when adding three of the four equal the following sums.. 20,22,24, and 27. This is what I have discovered so far but am really stuck. a+b+c+d=x 20= b+c+d or 20= x-a 22=x-b 24= x-c 27=x-d Thanks in advance to anyone who can solve this, I really appreciate it!!