Selected MCQ

Current Question
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 1
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 2
A vessel contains 90 litres. After removing and replacing milk, final quantity is ____.
  • A. 72
  • B. 72.9
  • C. 73.8
  • D. 74.7
Correct Answer: B
Explanation:
Replacement formula.
Related Question 3
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 4
A tower of height 15 m makes an angle of elevation 60°. Find the distance from the base.
  • A. 5 m
  • B. 8 m
  • C. 10 m
  • D. 12 m
Correct Answer: C
Explanation:
tan60 = h/d → d = 15/√3 = 10 m.
Related Question 5
The speed of the boat in still water is 60 km/h, and the current is 20 km/h. Find downstream and upstream speeds.
  • A. 35, 25
  • B. 80, 40
  • C. 40, 60
  • D. 50, 55
Correct Answer: B
Explanation:
Downstream = 80, upstream = 40.