Divide 72 rolls into 2 groups so the ratio is 3 to 5

If the ratio is 3:5 then there are 8 parts (3+5=8)

To find 1 part, divide 72 by 8 to give 9

Then multiply 9 by each of the numbers in the ratio:

3*9=37

5*9=45

So the rolls will be split into one group of 27 and one group of 45