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A lab needs 200ml of a 5% salt solution. They only have a 10% solution. How much 10% solution and water should be mixed?
- A. 100ml 10% solution, 100ml water
- B. 150ml 10% solution, 50ml water
- C. 160ml 10% solution, 40ml water
- D. 200ml 10% solution, 0ml water
Correct Answer: B
Rationale: Rationale:
1. Let x be the volume of the 10% solution needed and y be the volume of water needed.
2. The total volume of the final solution is 200ml, so x + y = 200.
3. The concentration of the final solution is 5%, so the amount of salt in the final solution is 0.05 * 200 = 10g.
4. The amount of salt in the 10% solution is 0.1x, and the amount of salt in the water is 0, so the total amount of salt in the final solution is 0.1x.
5. Since the total amount of salt in the final solution is 10g, we have 0.1x = 10.
6. Solving for x, we get x = 100ml.
7. Substituting x =
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Correct Answer: D
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- A. 400 cubic centimeters
- B. 4,000 cubic centimeters
- C. 40,000 cubic centimeters
- D. 400,000 cubic centimeters
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- A. 0.5 liters
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Correct Answer: A
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- A. 12
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- C. 30
- D. 40
Correct Answer: C
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