Data Sufficiency Questions with Solutions

Data sufficiency questions give a question and two (sometimes three) statements of information. Rather than finding the answer, you must decide whether the statements give enough information to answer it: statement I alone, statement II alone, either one alone, both together, or neither even together. The questions can be based on reasoning topics such as blood relations, ranking and coding, or on quantitative topics. Check each statement on its own first, then together only if neither works alone. You don't need to calculate the final answer. You only need to know whether a unique answer can be found. A common mistake is to carry information from one statement into the other when checking them separately. Another is to assume that "more information" always means "sufficient". If the statements leave two possible answers, the data is not sufficient. Practise the data sufficiency questions below. Each solution checks every statement individually and together.