Data Sufficiency Reasoning: Statement I and II Questions with Tricks and Answers for SSC

In a data sufficiency question, a question is given with two statements (I and II), and you have to decide whether the statements give enough data to answer the question. You do not have to find the exact answer in most cases. These data sufficiency reasoning tricks for SSC give the four standard options, a three-step method and solved examples on age, rank, code and days.

The Four Answer Options

Read the options of your exam carefully, because the order of the options can change from paper to paper.

Three-Step Method

1. Read the question and decide what exactly has to be found (a value, a person, a day or a yes/no).
2. Check Statement I alone. Write whether it is enough (yes or no).
3. Check Statement II alone. If both alone fail, combine them. If they still fail, choose "both together are not sufficient".

Solved Examples

Example 1 (days). What is the day today? I: The day after tomorrow is Thursday. II: Yesterday was a holiday.
From I, tomorrow is Wednesday and today is Tuesday. Statement II does not give the day. So I alone is sufficient.

Example 2 (age). What is the age of Ravi? I: Ravi is 5 years older than Sita. II: Sita is 20 years old.
I alone gives no number, and II alone does not give Ravi’s age. Together, Ravi is 20 + 5 = 25. Both together are sufficient.

Example 3 (comparison). Who is the tallest among A, B and C? I: A is taller than B. II: C is taller than A.
I alone gives A > B only. II alone gives C > A only. Together, C > A > B, so C is the tallest. Both together are sufficient.

Example 4 (rank). What is the rank of A in the class? I: A is above B. II: B is 5th.
A is above B means that A can be 1st to 4th, so the exact rank is not known. Both together are not sufficient.

Example 5 (code). What is the code of the word "good"? I: "good book" is coded as "ab cd". II: "good day" is coded as "ab ef".
The common word "good" has the common code "ab". Both together are sufficient (one statement alone gives two possible codes).

Example 6 (row). How many persons are there in a row? I: P is 7th from the left. II: P is 4th from the right.
Total = 7 + 4 − 1 = 10. Both together are sufficient.

Tips

• Do not solve the question fully. Only decide whether it can be solved.
• Never use outside knowledge unless the question allows it (for example, the days of a week).
• Check each statement alone first, even when you think that both are needed.
• If a statement gives an inequality (above, taller), it gives a range and not an exact value.

Quick Tips

• Check Statement I alone, then II alone, then both together, in that order.
• A relation like taller or above does not give an exact number.
• For total in a row, use left position + right position − 1.
• Do not solve for the full answer if sufficiency is clear.

Quick Revision Points

• There are four options: I alone, II alone, both together, both not sufficient.
• Always test each statement alone first.
• Position from left + position from right − 1 = total.
• Inequality statements usually need more data.
• Do not use outside facts unless the question allows.

Practice Questions With Answers

1. Who is the tallest among A, B and C? I: A is taller than B. II: C is taller than A. Are the statements sufficient?
   Answer: Both together are sufficient (C is the tallest)
2. What is the day today? I: Yesterday was Monday. Is I alone sufficient?
   Answer: Yes. Today is Tuesday
3. What is Neha’s age? I: Neha is 4 years younger than Ria. II: Ria is 30 years old.
   Answer: Both together are sufficient (Neha is 26)
4. Is X greater than 5? I: X is 10. Is I alone sufficient?
   Answer: Yes
5. How many students are in a class? I: Rohit is 10th from the top. II: Rohit is 15th from the bottom.
   Answer: Both together are sufficient (24 students)
6. What is the rank of A? I: A is above B. II: B is 5th.
   Answer: Both together are not sufficient
7. What is the code of "good"? I: "good book" is "ab cd". II: "good day" is "ab ef".
   Answer: Both together are sufficient (ab)
8. A two-digit number is divisible by 3 and by 10. It is less than 40. What is it?
   Answer: 30 (both statements together are sufficient)
9. What should you do if Statement I alone is enough?
   Answer: Choose the option for Statement I alone is sufficient
10. Do you always have to find the exact answer in data sufficiency?
    Answer: No. You only decide whether the data is enough

How to Practise This Chapter

Practise 10 questions every day and write the steps on paper. Then attempt timed sets from our practice papers and the previous year papers page. See all topics on the Reasoning notes page, read the previous topic Missing Number Reasoning and the next topic Number Analogy and Classification.

Frequently Asked Questions

What is data sufficiency in reasoning?

It is a question type in which you decide whether the given statements are enough to answer the question.

What are the four options in data sufficiency?

Statement I alone, Statement II alone, both together, and both together not sufficient.

Do I need to find the exact answer?

No. You only decide if the data is enough, although a quick calculation can help.

How do I solve data sufficiency questions?

Check I alone, check II alone, then check both together.

What if both statements give the same answer?

Then either statement alone is enough, so choose the option as per the paper (each alone is sufficient).

Can I use general knowledge?

Only for facts like the days of a week or the number of months.

What is the formula for the total in a row?

Position from left + position from right − 1.

Why is "A is taller than B" not enough?

Because it gives only an order and not the exact height.

Is data sufficiency asked in SSC exams?

It is asked less often than other topics, but it appears in some SSC papers and mock tests.

How much time should I take?

About 40 seconds.

What is the common mistake?

Combining the statements before checking each of them alone.

How can I practise?

Solve 5 questions a day and write the sufficiency of I, II and both for each of them.