Finley can make 5 batches of her favorite orange paint if she has 15 liters of red paint. You can find this by dividing 15 by 3. The information about the yellow paint is unnecessary information and can be overlooked in the context given, and by dividing 15 by 3, you get 5.
Write the equations:

Substitute for h:

Solve for s:

There were 280 downloads of the standard version. There were 1120 downloads of the high-quality version.
42 because 3:1 is 3 ounces for box a to 1 ounce for box b. So divide 128 by 3.
Because 3x2=6 and 2/3 equals 1/6