Selected MCQ

Current Question
A lotion contains 50% alcohol. How much water must be added to reduce the alcohol content to 25% in 9 ml?
  • A. 3 ml
  • B. 4 ml
  • C. 5 ml
  • D. 6 ml
Correct Answer: D
Explanation:
Using the dilution Equation yields 6 mL of water.
Related Question 1
A mixture of milk and water contains 20% water. How much water should be added to make it 25% ____.
  • A. 5%
  • B. 10%
  • C. 15%
  • D. Cannot be determined
Correct Answer: D
Explanation:
Initial quantity not given.
Related Question 2
Vessel P contains 62.5% alcohol, and Q contains 87.5%. If 2 L from P and 4 L from Q are mixed, find ratio of alcohol to water ____.
  • A. 16: 5
  • B. 14: 5
  • C. 16: 7
  • D. 19: 5
Correct Answer: D
Explanation:
Calculate the alcohol content and compare it with water.
Related Question 3
The price of an item is increased by 15%. By what percent must consumption be reduced to keep expenditure constant?
  • A. 10 20/23 %
  • B. 13 1/23 %
  • C. 16 2/3 %
  • D. 15 %
Correct Answer: B
Explanation:
Reduction = 15/115 ×100 = 13 1/23%.
Related Question 4
A tax is reduced by 20% and consumption increases by 10%. What is the net effect?
  • A. 20%
  • B. 18%
  • C. 15%
  • D. 12%
Correct Answer: D
Explanation:
Net effect = 0.8 × 1.10 = 0.88 → 12% decrease.
Related Question 5
A tax is reduced by 20% and consumption increases by 15%. What is the effect on revenue?
  • A. Increases by 8%
  • B. Decreases by 8%
  • C. No change
  • D. Increases by 10%
Correct Answer: B
Explanation:
Net effect = 0.8 × 1.15 = 0.92 → 8% decrease.