From the given, it is stated that after Amelia took 14 out of the box, Ramon took half of those which remained and he had 16 tiles. The number of tiles left after Amelia took hers is equal to twice of 16 which is equal to 32 tiles.
To determine the number of tiles during the start, we can add the 14 tiles from the calculated 32 tiles.
262.6/300% for the first 3 test if you were to add another test it would be 400% total and you need 360% of test grades to have an average of 90% and so 360 - 262.6 = 97.4%