SOLUTION: how many quarts of pure antifreeze must be added to 8 quarts of a 50% antifreeze solution to obtain a 60% antifreeze ?''.

Question 1091613: how many quarts of pure antifreeze must be added to 8 quarts of a 50% antifreeze solution to obtain a 60% antifreeze ?''.

Found 2 solutions by richwmiller, ikleyn:
Answer by richwmiller(17219)   (Show Source): You can put this solution on YOUR website!
1.00*x+.5*8=.6(8.0+x)
x+4=4.8+.6x
.4x=.8
x=2
check
2+4=.6(10)
6=6
check
Answer by ikleyn(52781)   (Show Source): You can put this solution on YOUR website!
.

Let x be the volume of the pure antifreeze under the question, in quarts. 8 quarts of the 50% antifreeze solution contain 0.5*8 quarts of the pure antifreeze. When we add x quarts of the pure antifreeze, the amount of pure antifreeze becomes x + 0.5*8 quarts. The total volume of liquid solution becomes (x+8) quarts. Therefore, the antifreeze concentration after adding becomes . According to the condition, it must be 60% = 0.6. It gives you an equation = 0.6. To solve it, first multiply both sides by (x+8). You will get x + 4 = 0.6*(x+8), or x + 4 = 0.6x + 4.8 ====> x - 0.6x = 4.8 - 4 ====> 0.4x = 0.8 ====> x = = 2. Answer. 2 quarts of the pure antifreeze must be added.

Solved.

There is entire bunch of introductory lessons covering various types of mixture problems
    - Mixture problems
    - More Mixture problems
    - Solving typical word problems on mixtures for solutions
    - Word problems on mixtures for antifreeze solutions (*)
    - Word problems on mixtures for alloys
    - Typical word problems on mixtures from the archive
in this site.

Among them, find the lesson on antifreeze marked by (*).
Read these lessons and become an expert in solving mixture word problems.

Also, you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this textbook in the section "Word problems" under the topic "Mixture problems".

RELATED QUESTIONS
how many quarts of pure antifreeze must be added to 8 quarts of a 50% antifreeze solution (answered by ikleyn)
How many quarts of pure antifreeze must be added to 7 quarts of a 50% antifreeze solution (answered by stanbon)
how many quarts of pure antifreeze must be added to 6 quarts of a 50% antifreeze solution (answered by josgarithmetic)
How many quarts of pure antifreeze must be added to 8 quarts of a 10% antifreeze solution (answered by josgarithmetic)
how many quarts of pure antifreeze must be added to 4 quarts of a 50% antifreeze solution (answered by josgarithmetic,greenestamps)
How many quarts of antifreeze must be added to 8 quarts of a 50% antifreeze solution to... (answered by nerdybill)
how many quarts of pure antifreeze must be added added to 9 quarts of a 40% antifreeze... (answered by galactus)
How many quarts of pure antifreeze must be added to 9 quarts of a 40% antifreeze solution (answered by jorel1380)
how many quarts of pure antifreeze must be added to 4 quarts of a 20% antifreeze solution (answered by lwsshak3)