You can buy 20 fluid ounces of shampoo for $4.40 or 24 fluid ounces for $4.80. which is the better buy? explain.

First you have to do 440 / 20, which is 22 cents per bottle
Next you have to do 480 / 24, which is 20 cents per bottle
20 < 22, so the 24 ounces of shampoo is the correct answer.

Ok, so you put $4.40 over 20 ounces which will get you $ 0.22 per ounce
You do the same for the other one.

4.80 over 24 ounces which is $ 0.20 per ounce
So the better price would be 24 fluid ounces of shampoo for $ 4.80