You'll find a time bar under the board, with a marker running from right to left. The number on the left hand side shows you your new rating if you fail the puzzle. In this case it would be 1338.
The number above the marker shows the rating you would obtain if you solved the puzzle correctly. This decreases constantly until it reaches your current rating. After that you won't gain any points even if you find the right solution, so you can only gain points if your time has not expired.