SOLUTION: for a certain experiment, a student requires 100 cubic centimeters of a solution that is 8% HCl, the storeroom has only solutions that are 15%HCl and 5% HCl, How many cubic centime

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Question 1132315: for a certain experiment, a student requires 100 cubic centimeters of a solution that is 8% HCl, the storeroom has only solutions that are 15%HCl and 5% HCl, How many cubic centimeters of each available solution should be mixed to get 100 cubic centimenters of 8% HCl.
Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
x of the 15%
100-x of the 5%

15x%2B5%28100-x%29=8%2A100

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


For a quick non-algebraic solution to this problem (and a huge number of similar problems), try this....

(1) 8% is 3/10 of the way from 5% to 15% (think of it on a number line -- 15-5 = 10; 8-5 = 3 --> 8 is 3/10 of the way from 5 to 15).

(2) That means 3/10 of the mixture must be the 15% solution.

ANSWER: 3/10 of 100cc = 30cc of 15%; so 70cc of 5%.