John is making punch. How many cups of 50% juice should he add to a drink that contains 10% juice if he wants to make 15 cups of punch containing 20% juice? (How many cups of each drink)
Define one variable based on the percentage of which is being asked.
Set up table (Which wants the percent and amt of Mixture A and Mixture B)
Lets make a equal the amount of mixture a and b the amount of mixture b. You can made an equation .10a+.50b=.20(15) and a+b=15. So then you make the system of equations: .10a+.50b=3 a+b=15 I would substitute b in the first equation with b=15-a to get the single equation .10a+.50(15-b)=3 and then solve for b. .10a+7.5-.5a=3 -.4a+7.5=3 -.40b=-4.5 a=11.25 With that value of a you can find that b=3.75 Therefore you you have to mix 11.25 cups of 10% juice with 3.75 cups of 50% juice to get 15 cups of 20% juice.
This is how I would solve the question. I don't really know what the question means by setting up a table so I hope this method is fine. If it is not please let me know in the comments so that I can try to fix it. I hope this helps.
P.S. Let me know if you want me to try to explain to you how I got my first equation. You have to use knowledge that you will eventually learn in chemistry when going over the unit that introduces you to solutions.
