### GMAT Practice Question Source:

### Difficulty: 600-700 Level

### GMAT Study Guide Module:

### GMAT Timing Tips:

**Matrix boxes**: For time efficiency, I generally recommend using a matrix box whenever you see a question that divides up a group into two categories in two different ways. In this question, George’s books can be divided into fiction and nonfiction (1st way) and hardcover and paperback (2nd way). An example of how to draw the matrix boxes for each statement (and the combination of statements) is shown in this post on GMAT Club. I find that matrix boxes improve efficiency because they help you to see the information in an organized way. You can also mark the boxes that you need to fill in to answer the question, so that you know exactly when you can stop because you have the information you need. In this case, we are solving for the total (the bottom right box, if you draw a total column on the right and a total row on the bottom).

### Have a question that you want Jeff to answer about this GMAT practice question?

Ask your question in any of the following ways:

**GMAT Club**: See the full question and ask your question in this thread: George has a total of B books in his library, 25 of which are hardcover…