Selected MCQ

Current Question
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 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
In what ratio should water be mixed with spirit to gain 20%?
  • A. 2:5
  • B. 1:5
  • C. 3:5
  • D. 4:5
Correct Answer: B
Explanation:
The profit method yields a 1:5 ratio.
Related Question 3
Ratio of speed of boat to stream is 36:5. Time downstream is 5h 10min. Find upstream time.
  • A. 5h 50m
  • B. 6h
  • C. 6h 50m
  • D. 12h 10m
Correct Answer: C
Explanation:
Use the ratio method for speeds.
Related Question 4
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.
Related Question 5
The speed of the boat in still water is 5 km/h. It travels upstream and downstream the same distance. Find stream speed.
  • A. 5 km/h
  • B. 8 km/h
  • C. 10 km/h
  • D. 15 km/h
Correct Answer: A
Explanation:
Equal time implies that stream speed equals still-water speed.