A punch recipe calls for 7 parts water to 2 parts powder. You make 108 fluid ounces of punch. How many fluid ounces of each ingredient do you need?
since the punch recipe calls for 7 parts water and 2 parts powder, that means it consists of 7 + 2 = 9 parts total.
because you make 108 fluid ounces of punch, we do 108 / 9 = 12.
now we multiply 12 by the 7 parts of water and the 2 parts of powder, to get that you need 84 fluid ounces of water and 14 fluid ounces of punch.
hope this helped! sorry if my explanations didn't make much sense. feel free to ask any further questions