Data sufficiency problem is a challenging type of problems. To solve such type of problems, you need to learn if the data provided are sufficient to solve the problem or not. Let’s take an example to understand this type of problems.

## Data Sufficiency Problem Example

How many quarts of oil will a car burn during a 30 km trip?

**(1) The car burns half a quart of oil every 10 km.**

**(2) At a price of $0.30 per quart, the car uses $0.45 worth of oil during the trip.**

- To answer the question, statement (1) alone is sufficient, but statement (2) alone isn’t sufficient.
- To answer the question, statement (2) alone is sufficient, but statement (1) alone isn’t sufficient.
- Both statements together suffice to answer the question asked. However, each statement alone is not sufficient.
- Each statement alone suffice to answer the question.
- Statement (1) and (2) alone or together are not sufficient to answer the question, and further data are required to answer the question.

## Data Sufficiency Problem Solution

**The correct answer is (D)**. To answer the question, you need to know the rate (the number of kilometers per quart) at which the car burns oil. Statement (1) provides the information you need. A half quart of oil is burned per 10 km; therefore, the rate is 10km/0.5quart= 20 km/quart. Although you don’t need to do the math, the answer to the question is 30/20 = 1.5 quarts. Based on that answer, either choice (A) or (D) could be the right answer.

Nevertheless, statement (2) alone also provides the data required to conclude the rate at which the car burns oil. The amount of oil used = $0.45 per quart/ $0.35. Again, although you don’t need to do the math, the quotient (and the answer to the question) is 1.5 quarts. Because either statement (1) or (2) alone is sufficient to answer the question, then, choice (D) is the correct answer.

**Also read: Critical Reasoning: Evaluating An Argument**

## Final Word

You can find the right answer without doing the math. From statement (1), you would know the rate from which you can get the number of quarts of oil burnt if you know the the distance crossed in km which is 30 km as found in the problem. Also, from statement (2), you would know the rate from which you can calculate the number of quarts burnt in the trip.