You need a 45% alcohol solution. On hand, you have a 350 mL of a 15% alcohol mixture. You also have 70% alcohol mixture. How much of the 70% mixture will you need to add to obtain the desired solution?

Question

You will need
________ mL of the 70% solution

Answer 1

Juan needs to mix a 10% acid solution with a 50% acid solution to create 100 millileters of a 34% solution. How many millileters of each solution must Juan use?

______ millileters of 10% solution and
________ millileters of 50% solution.

Answer 2

amount of the 70% solution needed ---- x ml
So your final amount will be x + 350 ml
.17(350) + .70x = .45(350+x)

suggestion: multiply each of the 3 terms by 100 to get rid of those decimals
17(350) + 70x = 45(350+x)

now just solve for x