Ratio & Proportion Quiz: Quantitative Aptitude Practice

Spoilers! These are the Starter quiz’s answers. Easy, Medium, Hard and Mixed rounds show their own answers when you finish.

1. If A:B = 2:3 and B:C = 4:5, then A:B:C is:

   • 6:9:10
   • 8:15:12
   • 4:6:5
   • 8:12:15

   Answer: 8:12:15. Make B equal: A:B = 8:12 and B:C = 12:15, so A:B:C = 8:12:15.

2. Rs 7,200 is divided among three people in the ratio 3:4:5. What is the largest share?

   • Rs 3,000
   • Rs 2,400
   • Rs 2,800
   • Rs 3,600

   Answer: Rs 3,000. Total parts = 12, so one part = Rs 600. The largest share is 5 × 600 = Rs 3,000.

3. What is the fourth proportional to 6, 9 and 14?

   • 18
   • 24
   • 21
   • 28

   Answer: 21. 6:9 = 14:x, so x = (9 × 14)/6 = 21.

4. What is the mean proportional between 9 and 64?

   • 36
   • 32
   • 28
   • 24

   Answer: 24. Mean proportional = square root of (9 × 64) = square root of 576 = 24.

5. What is the third proportional to 16 and 24?

   • 36
   • 32
   • 40
   • 48

   Answer: 36. 16:24 = 24:x, so x = 24²/16 = 576/16 = 36.

6. Two numbers are in the ratio 5:7. If 6 is added to each, the ratio becomes 3:4. What is the smaller number?

   • 25
   • 35
   • 30
   • 42

   Answer: 30. (5x + 6)/(7x + 6) = 3/4 gives 20x + 24 = 21x + 18, so x = 6. The smaller number is 5 × 6 = 30.

7. A bag contains 50 paise, Rs 1 and Rs 2 coins in the ratio 4:3:2. The total value is Rs 180. How many Rs 1 coins are there?

   • 60
   • 80
   • 40
   • 45

   Answer: 60. One set of 4 + 3 + 2 coins is worth 2 + 3 + 4 = Rs 9. Rs 180 makes 20 sets, so there are 3 × 20 = 60 Rs 1 coins.

8. If A:B = 3:4, what is (5A + 2B):(3A + 4B)?

   • 25:23
   • 19:25
   • 23:28
   • 23:25

   Answer: 23:25. Put A = 3 and B = 4: (15 + 8):(9 + 16) = 23:25.

9. The incomes of A and B are in the ratio 3:4 and their expenditures in the ratio 5:7. If each saves Rs 6,000, what is A's income?

   • Rs 48,000
   • Rs 36,000
   • Rs 30,000
   • Rs 42,000

   Answer: Rs 36,000. 3x - 5y = 6,000 and 4x - 7y = 6,000. Solving gives y = 6,000 and x = 12,000, so A earns 3 × 12,000 = Rs 36,000.

10. What is the compound ratio of 2:3, 6:11 and 11:2?

    • 1:2
    • 2:1
    • 3:2
    • 4:3

    Answer: 2:1. Multiply the antecedents and the consequents: (2 × 6 × 11):(3 × 11 × 2) = 132:66 = 2:1.