Data Sufficiency
Data Sufficiency
Data sufficiency is a common type of question in reasoning ability tests that assesses your ability to analyse and determine whether the given data is sufficient to answer a specific question or solve a problem. In data sufficiency questions, you are typically provided with a question followed by two or more statements, and you need to determine if the information in those statements is enough to answer the question.
Example 1: Is angle XYZ a right angle? Statement 1: Angle XYZ is 90 degrees. Statement 2: The sum of angles XYW and WYZ is 90 degrees.
Solution: In this example, let's analyse each statement individually and then consider them together:
Statement 1: Angle XYZ is 90 degrees. This statement directly states that angle XYZ is a right angle. Therefore, Statement 1 alone is sufficient to determine that angle XYZ is a right angle.
Statement 2: The sum of angles XYW and WYZ is 90 degrees. This statement provides information about the sum of two angles but does not directly reveal the measure of angle XYZ. Therefore, Statement 2 alone is not sufficient to determine if angle XYZ is the right angle.
Combining both statements: When we consider both statements together, Statement 1 guarantees that angle XYZ is 90 degrees. Statement 2, although providing additional information, is not necessary. Hence, together they are sufficient to answer the question.
In this example, the answer is (C): both statements together are sufficient, but neither statement alone is sufficient.
Example 2: What is the value of variable X? Statement 1: X + 5 = 10. Statement 2: X minus 2 = 7.
Solution: Let's analyse each statement individually and then consider them together:
Statement 1: X + 5 = 10. This statement provides an equation relating X to the value 10. By solving the equation, we find that X = 5. Therefore, Statement 1 alone is sufficient to determine the value of X.
Statement 2: X minus 2 = 7. This statement also provides an equation relating X to the value 7. By solving the equation, we find that X = 9. Therefore, Statement 2 alone is sufficient to determine the value of X.
Combining both statements: When we consider both statements together, we have two different equations: X + 5 = 10 and X + 2 = 7. Solving both equations, we find that X = 5 and X = 9. Since the two equations yield different values for X, both statements alone are not sufficient to determine the value of X.
In this example, the answer is (A): Statement 1 alone is sufficient, but Statement 2 alone is not sufficient.
Data sufficiency questions require careful analysis of the given statements to determine if they provide enough information individually or collectively to answer the given question. It's important to evaluate each statement independently and then consider their combined impact. Regular practise with data sufficiency questions can help improve your analytical skills on reasoning ability tests.
