This page is part of my unofficial solutions manual to the GRE Paper Practice Book (2e), a free resource available on the ETS website. They publish the questions; I explain the answers. If you haven’t worked through the Practice Book, give Section 5 a shot before reading this!

5.18: Gas Tax Facts

Here’s another one of those “triple true-false” questions. Just as in a Reading Comprehension passage, we have to step through each answer choice and check to see if it’s supported by the data. Moreover, just like a Reading Comprehension question, the devil is in the details: we need to read carefully, so as not to be taken in by tricky wording.

First, let’s consider answer (A). At a glance it might seem that this statement is supported by the bar chart, but look again: the bar chart lists gas tax revenue “as a percent of total retail gasoline sales,” but the statement concerns France’s gas tax revenue “as a percent of total tax revenue.” We don’t have any information about the distribution of France’s total tax revenue — only Germany’s. Answer (A) is therefore incorrect.

How about answer (B)? Again, this statement refers to figures that aren’t actually presented in the graphs, which don’t mention the actual “price per gallon” in any of the nine countries. It may be tempting to assume that gas will be more expensive in Norway, since gas taxes are higher there than in Spain. But there are all sorts of other factors — transport costs, for example — that might affect the per-gallon price in each of the two countries. Because we can’t say how those other factors will influence prices, we reject answer (B) for insufficient evidence.

At this point, we know answer (C) is correct, because we’ve ruled out (A) and (B), and at least one answer is correct in every multiple-choice GRE question. To see why (C) is right, look at the pie chart. Germany’s gas tax revenue is given as 20.4% of the total, and the tobacco tax revenue is 5.6%. Because 20.4/5.6 is greater than 3, the gas tax revenue must be more than triple the tobacco tax revenue.

Math Review Reference

For more on this topic, see the following section of the GRE Math Review:

• 4.1: Graphical Methods for Describing Data (pp. 62-65)