Ratio and Proportion Questions for SSC Selection Post: Practice Top Questions Now

Are you preparing for the upcoming SSC Selection Post exam? If yes, then you already know that the Quantitative Aptitude (Math) section is where the real competition happens. Inside this math section, there is one magic chapter that controls almost half of the syllabus: Ratio and Proportion.

Many students get scared of math because they hate memorizing long formulas. But here is a big secret: Ratio and Proportion does not need any tough formulas! It is a very simple topic based on common daily-life counting. Even better, once you learn this single chapter, you can easily solve questions from other hard chapters like Ages, Partnerships, Mixtures, and Time & Work without breaking a sweat.

In this blog, we have explained this topic in the simplest words possible. We have also gathered the top exam-level questions that the Staff Selection Commission (SSC) repeats every single year.

What is Ratio and Proportion? (Explained in Simple Words)

You do not need to be a math genius to understand this. Let us break it down using daily life examples.

What is a Ratio? A ratio is simply a way to compare two things by cutting them down to their smallest parts. For example, suppose you have Rs. 200 and your friend has Rs. 400. If we compare them, we cut both numbers by 200. It becomes 1 and 2. We write this as 1:2. This is the ratio! It simply means that for every 1 rupee you have, your friend has 2 rupees.

What is a Proportion? Proportion simply means that two ratios are exactly equal to each other. The sign for proportion is four dots (::). For example, if the ratio of boys to girls in Room A is 2:3, and in Room B it is also 2:3, we can say both rooms are in proportion.

The Golden Trick: You only need to learn the “1 Unit Value” trick. Instead of using the long ‘x’ method from your school days, always find the value of 1 unit. Once you find what 1 unit equals, you can solve any question in 10 seconds!

Important Ratio & Proportion Questions for SSC Selection Post

Now that you know the basics, it is time to test yourself. Grab a pen and solve these highly repeated Ratio and Proportion questions that perfectly match the SSC Selection Post exam level.

Q1. If A : B = 3 : 4 and B : C = 8 : 9, then find the ratio of A : B : C.

(A) 3 : 8 : 9
(B) 6 : 8 : 9
(C) 12 : 32 : 36
(D) 6 : 12 : 9

Answer: (B) 6 : 8 : 9

Explanation: ‘B’ is common in both ratios. In the first ratio, B is 4. In the second, B is 8. Make them equal by multiplying the first ratio by 2. A : B becomes 6 : 8. Now B is 8 in both places. So, A : B : C = 6 : 8 : 9.

Q2. An amount of Rs. 2400 is divided among Ram, Shyam, and Mohan in the ratio 2 : 3 : 5. What is the share of Shyam?

(A) Rs. 480
(B) Rs. 720
(C) Rs. 1200
(D) Rs. 800

Answer: (B) Rs. 720

Explanation: Total ratio units = 2 + 3 + 5 = 10 units. Total money given = Rs. 2400. So, 10 units = 2400. 1 unit = 2400 / 10 = Rs. 240. Shyam has 3 units. Shyam’s share = 3 × 240 = Rs. 720.

Q3. Find the fourth proportion to 5, 10, and 15.

(A) 20
(B) 25
(C) 30
(D) 35

Answer: (C) 30

Explanation: Let the fourth proportion be ‘x’. The rule is: First × Fourth = Second × Third.

5 × x = 10 × 15

5x = 150

x = 150 / 5 = 30.

Q4. Two numbers are in the ratio 5 : 7. If their difference is 18, find the larger number.

(A) 45
(B) 54
(C) 63
(D) 72

Answer: (C) 63

Explanation: Let the numbers be 5 units and 7 units. Difference in ratio = 7 – 5 = 2 units. We know the real difference is 18. So, 2 units = 18. 1 unit = 18 / 2 = 9. The larger number is 7 units. So, 7 × 9 = 63.

Q5. Find the mean proportion between 4 and 36.

(A) 12
(B) 16
(C) 20
(D) 24

Answer: (A) 12

Explanation: The simple formula for mean proportion is the square root of (a × b).

Square root of (4 × 36) = Square root of 144.

The square root of 144 is 12.

Q6. A box contains Rs. 1, 50-paisa, and 25-paisa coins in the ratio 1 : 2 : 4. If the total money in the box is Rs. 60, find the number of 25-paisa coins.

(A) 20
(B) 40
(C) 60
(D) 80

Answer: (D) 80

Explanation: First, find the value in rupees:

Rs. 1 × 1 unit = Rs. 1

50p × 2 units = Rs. 1

25p × 4 units = Rs. 1

Total value in ratio = 1 + 1 + 1 = 3 units.

Total real money = Rs. 60.

3 units = 60, so 1 unit = 20.

Number of 25-paisa coins is 4 units.

So, 4 × 20 = 80 coins.

Q7. The income of A and B is in the ratio 4 : 5. Their expenses are in the ratio 3 : 4. If both of them save Rs. 3000 each month, what is the income of A?

(A) Rs. 9000
(B) Rs. 12000
(C) Rs. 15000
(D) Rs. 18000

Answer: (B) Rs. 12000

Explanation: Income ratio = 4 : 5. Expense ratio = 3 : 4. Difference for A (Income – Expense) = 4 – 3 = 1 unit. Difference for B (Income – Expense) = 5 – 4 = 1 unit. This 1 unit is their saving. We know they save Rs. 3000. So, 1 unit = Rs. 3000. Income of A = 4 units = 4 × 3000 = Rs. 12000.

Q8. The third proportion to 16 and 24 is?

(A) 32
(B) 36
(C) 40
(D) 48

Answer: (B) 36

Explanation: The formula for the third proportion of two numbers (a and b) is (b × b) / a.

Here a = 16, b = 24.

(24 × 24) / 16 = 576 / 16 = 36.

Q9. Two numbers are in the ratio 3 : 5. If 10 is added to both the numbers, the new ratio becomes 5 : 7. Find the smaller number.

(A) 15
(B) 20
(C) 25
(D) 30

Answer: (A) 15

Explanation: Look at the ratio gap.

Old ratio = 3 : 5

New ratio = 5 : 7

The gap for both is exactly 2 units (5-3=2 and 7-5=2). This 2 unit increase happened because we added 10. So, 2 units = 10. 1 unit = 5. Smaller number = 3 units = 3 × 5 = 15.

Q10. A sum of money is divided among A, B, and C in such a way that A gets double of what B gets, and B gets double of what C gets. Find the ratio of their shares (A : B : C).

(A) 1 : 2 : 4
(B) 4 : 2 : 1
(C) 2 : 1 : 2
(D) 4 : 1 : 2

Answer: (B) 4 : 2 : 1

Explanation: Start from the end. Let C get 1 unit. B gets double of C. So, B = 2 units. A gets double of B. So, A = 4 units. The ratio A : B : C = 4 : 2 : 1.

5 Simple Tips to Prepare Ratio & Proportion

You do not need to be a topper to score full marks in this topic. Just follow these 5 easy tips:

• Avoid the ‘x’ Method: School methods using ‘x’ take too much time. Always find the value of “1 unit” and multiply it to get your final answer.
• Memorize the 3 Main Formulas: SSC Selection Post always asks 1 direct question on Mean Proportion, Third Proportion, or Fourth Proportion. Write these 3 small formulas on a paper and stick them on your wall.
• Play with the Options: Sometimes you do not even need to solve the question. If the question asks for A’s income, and A’s ratio is 4, check the options. The correct answer must be fully divisible by 4.
• Master the Coin Questions: The “bag of coins” question is SSC’s favorite. Learn how to convert the number of coins into rupee value to solve it quickly.
• Practice Previous Year Papers: The SSC board copies its own math questions every year. Solve the previous year’s questions of SSC Selection Post (Matriculation, 10+2, and Graduate level). You will see the exact same logic repeating!

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FAQs: Ratio & Proportion for SSC Selection Post

1. Is Ratio and Proportion a difficult chapter for SSC Selection Post?

No, not at all! It is one of the easiest and most scoring chapters in the math section. The questions are mostly based on simple daily life money distribution and basic fractions.

2. How many questions come from this topic in the exam?

You can comfortably expect 1 to 2 direct questions from this chapter. Also, you will need the logic of this chapter to solve Data Interpretation (DI) and Mixture questions.

3. Do I need to memorize big formulas for this chapter?

No. You only need to remember three tiny formulas: Mean Proportion, Third Proportion, and Fourth Proportion. The rest of the chapter runs purely on logic.

4. Are these questions useful for other SSC or Railway exams too?

Yes, absolutely! The syllabus and question difficulty for SSC Selection Post, SSC CHSL, SSC MTS, and Railway exams are exactly the same for this chapter.

5. What is the trick to solve “Adding/Subtracting to a ratio” questions?

The best trick is to check the gap between the old ratio and the new ratio. If the gap is equal on both sides, just match that gap with the real number given in the question.