SOLUTION: A certain volume of a solution 90% pure acid and 10% water is mixed with another solution containing 97% acid and 3% water If the mixture obtained is 21 litres of 95% acid solutio

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: A certain volume of a solution 90% pure acid and 10% water is mixed with another solution containing 97% acid and 3% water If the mixture obtained is 21 litres of 95% acid solutio      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 1123990: A certain volume of a solution 90% pure acid and 10% water is mixed with another solution containing 97% acid and 3% water If the mixture obtained is 21 litres of 95% acid solution, what is the difference between the volumes of the two solutions mixed?
Found 3 solutions by josgarithmetic, josmiceli, ikleyn:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
x, volume used for the 90% acid solution

90x%2B%2821-x%2997=95%2A21
-
90x%2B21%2A97-97x=95%2A21
-3x=95%2A21-97%2A21
x=2%2A21%2F3
x=14

The two volume quantities: 14 and 6 liters
Their difference: 8 liters


Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = the liters of 90% mixture used
+21+-+x+ = liters of the 97% mixture
———————————
+%28+.9x+%2B+.97%2A%28+21+-+x+%29+%29+%2F+21+=+.95+
+.9x+%2B+20.37+-+.97x+=+.95%2A21+
+-.07x+=+-+20.37+%2B+19.95+
+.07x+=+.42+
+x+=+6+
And
+21+-+x+=+15+
The difference between the volumes is
+15+-+6+=+9+ liters
———————————
Check:
+%28+.9%2A6+%2B+.97%2A15+%29+%2F+21+=+.95+
+%28+5.4+%2B+14.55+%29+%2F+21+=+.95+
+19.95+=+19.95+
OK

Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.
The solution by @josmiceli is correct.

The solution by @josgarithmetic is wrong.

Simply ignore it.