Let's say there are 12 boxes of cheese in the original order. Draw a table with 4 rows and 3 columns. Shade exactly 3 of the rows (the entire row). So you should shade in 9 boxes total with 3 left unshaded.
Those 9 shaded boxes are then distributed equally among the 3 restaurants. So each restaurant gets 9/3 = 3 boxes
Comparing those 3 boxes to the original 12 forms the fraction: 3/12 = 1/4
So each restaurant gets 1/4 of the original order
Answer: 1/4
Note: another way to do this is to multiply 1/3 by 3/4 to get 1/4
