Question 1158396: how many mL of 50% dextrose solution and how many mL of water are needed to prepare 100 mL of 15 % dextrose solution? Found 2 solutions by greenestamps, josgarithmetic:Answer by greenestamps(13200) (Show Source):
x mL of the 50% dextrose, plus (100-x) mL of water (0% dextrose), equals 15% of 100 mL:
ANSWER: 30 mL of 50%; 70 mL of water
(2) Basically the same solution, informally....
The water is 0% dextrose, so all of the dextrose comes from the 50% dextrose solution.
In the final mixture, the amount of dextrose is 15% of 100 mL, or 15 mL.
The 50% dextrose solution is one-half dextrose; to get 15mL of dextrose, you need 30 mL of solution.
(3) A completely different method of solving....
You are mixing 0% and 50% dextrose to get 15% dextrose.
15% is 15/50 = 3/10 of the way from 0% to 50%.
So 3/10 of the mixture is the 50% dextrose.
3/10 of 100 mL is 30 mL.
(