SOLUTION: how many cubic centimeters of a 25% antibiotic solution should be added to 10 cubic centimeters of a 60 % antibiotic solution in order to get a 30 % antibiotic solution.

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Question 970048: how many cubic centimeters of a 25% antibiotic solution should be added to 10 cubic centimeters of a 60 % antibiotic solution in order to get a 30 % antibiotic solution.
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
x=cc of 25% solution

10 cc * 0.60 (60%) + x cc * (.25) =(x+10)cc * (.30)
The right is the new solution, x of the added + 10 of what is present already.
Multiply:
6 + (0.25) x = .30x + 3 ; We distribute the .30 over the (x +10)
6+ 0.25 x =0.30 x +3
Subtract 6 from each side
0.25 x =0.30 x -3
Now subtract 0.30 x from both sides
-0.05 x=-3
Multiply both sides by (-1) ; 0.05 x =3
Divide both sides by 0.05
x=0/0.05
x=60 cc
Check
60 cc *0.25 + 10 cc *0.60=15 + 6 = 21
70 cc *0.30=21
The answer is 60 cc