Ratio & Proportion · Question 23 · Medium
Ratio & Proportion question 23
The numbers of students in three sections of a class are in the ratio 2 : 3 : 5. If 20 students are added to each section, the ratio becomes 4 : 5 : 7. How many students were there in all three sections originally?
- 160
- 120
- 100
- 80
Answer and explanation
Answer: C. 100
Explanation: Let the sections have 2k, 3k, 5k students. (2k + 20)/(3k + 20) = 4/5 gives 10k + 100 = 12k + 80, so k = 10. Check: 40 : 50 : 70 = 4 : 5 : 7. Original total = 10k = 100.
Previous: What is the sub-duplicate ratio of 64 : 121? · Next: If A : B = 5 : 3 and A − B = 18, what is A + B?
Practise ratio & proportion
Try a fresh set of ratio & proportion questions with an explanation after every answer, free and without signing up: Ratio & Proportion practice. Or sit a full placement mock test.
More ratio & proportion questions
- What is the ratio of 45 minutes to 2 hours?
- If (4x + 3y) : (3x + 5y) = 6 : 7, what is x : y?
- What is the sub-duplicate ratio of 64 : 121?
- If A : B = 5 : 3 and A − B = 18, what is A + B?
- The monthly salaries of Ravi and Sunil are in the ratio 5 : 4. If Ravi's…
- Two numbers are in the ratio 2 : 3 and their product is 1350. What is their sum?
- If A : B = 2 : 3, B : C = 5 : 7 and C : D = 3 : 4, what is A : D?
- ₹2,940 is divided among A, B and C such that 3 times A's share = 5 times B's…
- x varies directly as y and inversely as z. When y = 12 and z = 4, x = 9. What…
- The ratio of boys to girls in a coaching class is 5 : 3. If 8 boys leave and 8…
More quantitative aptitude practice
Averages · Problems on Ages · Mixtures & Alligation · Time & Work · Pipes & Cisterns · Time, Speed & Distance · Problems on Trains · Boats & Streams
LogicWiz Exams home · All practice topics · Placement mock tests · Daily 10 challenge