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Answer: BSet 15: Systems of Equations (Advanced)
Explanation
A solution is 15% alcohol. How much pure alcohol must be added to 60 liters to increase the concentration to 25% alcohol?
A.
6 liters
B.✓ Correct
8 liters
C.
10 liters
D.
12 liters
Detailed Explanation
Choice B is correct. Choice B is the correct answer. Let = liters of pure alcohol (100%) to add. Equation: Amount of alcohol before = amount after 0.15(60) + 1.00(x) = 0.25(60 + x)$9+ x = 15 + 0.25 x0.75x = 6x = 8$$ Solution: 8 liters of pure alcohol Verification: \frac{9 + 8}{60 + 8} = \frac{17}{68} = 0.25 = 25%$ ✓ Strategic Tip: Pure substance = 100% concentration. Other choices fail verification.
Key Steps:
•
The correct answer is 8 liters
Why others are wrong:
A: Choice A is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
D: Choice D is incorrect and may result from a calculation error.
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