posted by Bob .
Four players are playing a game involving choosing squares on a grid of size 3×8. Each player chooses a random square on the grid, then all players reveal their choices and a token is placed in the center of each of these squares.
The probability that the tokens form the vertices of a "non-degenerate" rectangle can be expressed as a/b where a and b are coprime positive integers. What is the value of a+b?
1. Players are allowed to have selected the same squares.
2. There is no restriction on their choices.
3. A degenerate rectangle has 0 area.
4. Squares are rectangles.