This article will cover the A-Z of Data Sufficiency, covering the type and pattern of Data Sufficiency questions followed by few solved examples.

Data Sufficiency questions test your knowledge of basic math facts and skills coupled with reasoning, analytical and problem solving abilities. Each Data Sufficiency item presents you with a question where you need to decide whether or not the information presented along with the question would be sufficient to answer the question.

The challenge in DS questions, as they are popularly called, is not question solving but rather establishing whether the question has a solution or not. A special array of five answer choices is provided, each of which categorizes the relationship between the question and the information provided in a different way. You must select the answer choice that describes this relationship accurately.

Let's have a cursory look at these answer options which generally feature in this question type

- Students often confuse the different answer options, and end up marking the incorrect choice. Always double check whether you are marking the correct option, and do not assume that the examiner would always present the options in a default order.
- Go through the answer options to check whether the order of statements is as expected.

- The sum of the two numbers is greater than 50.
- Each of the numbers is greater than 10.

- Statement A alone is not sufficient to answer the question and this can be proved by examples. If the two numbers are 30 and 31, their sum is greater than 50 and their product is greater than 100; but if the two numbers are 50 and 1, though their sum is greater than 50, their product is only 50, and less than 100.
- Statement B is sufficient. If both of the numbers are greater than 10, then their product must be greater than 10 x 10, or greater than 100.
Hence only second statement is sufficient to solve the question.

**Option B**is the answer.

- 91 <x< 97
- x is a factor of 121

In second statement, the factors of 121 are 1, 11 and 121. Here 1 and 121 are not prime numbers whereas 11 is a prime number. Hence in this case 'x' may or may not be a prime number.

Hence, only the first statement is sufficient to solve the question. Option A is the answer.

Hence, only the first statement is sufficient to solve the question. Option A is the answer.

- Remember, even if a question has an answer as 'no', even then it is a valid answer.

- x
^{2}= 36 < 97 - x is a natural number.

- From statement A, we have x = 6 or - 6. In both the cases x is not equal to - 5. Hence first statement is sufficient to get the answer.
- Statement B says that x is a natural number. Since x is a natural number, it cannot be negative. Hence it is not equal to - 5. So, the second statement is also sufficient to solve the question.

Hence, both statements are independently sufficient to answer the question.**Option C**is the answer.

- To conclude, it is very important to read the question carefully in the case of Data Sufficiency questions.
- One major mistake committed by a number of students is that when the answer has to be yes/no and normally whenever you get the answer as no, you mark the answer as insufficient.
**Remember:**'NO' is also an answer for Data Sufficiency questions.