Solve Multiple-Graph Problems on the SAT

By Geraldine Woods, Ron Woldoff

As if one graph weren’t challenging enough, some questions on the SAT Math test use two graphs in one problem. No need to fret, though — there is a simple art to answering multiple-graph questions.

To get started, take a look at these two graphs.

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You must read these graphs together. The second graph is a bar graph going from 0 to 100 percent. Read the graph by subtracting to find the appropriate percentage. For example, in 1990, “Grandparents won’t donate a building” begins at 20 percent and goes to 50 percent, a difference of 30 percent. You’ve fallen into a trap if you say that “Grandparents won’t donate a building” was 50 percent. In 1993, “Just felt like it” goes from 80 percent to 100 percent, which means it was actually 20 percent.

The first graph gives you the number of SAT test-takers in thousands. (By the way, these aren’t real numbers.) Be sure to look at the labels of the axes. For example, Thousands along the side axis tells you that in 1990, there weren’t 100 test-takers but 100,000. Using the two graphs together, you can find out the number of test-takers who took the SAT for a particular reason. For example, in 1991, 200,000 students took the test. Also in 1991, “Couldn’t hack into computer and record an 800” (from 70 to 80, or 10 percent) made up 10 percent of the reasons for taking the SAT. Multiply 10 percent or

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On the test, you may encounter two to three questions about a particular graph. Answer the following question based on the two graphs.

  1. The number of students who took the SAT in 1994 because their grandparents wouldn’t donate a building was how much greater than the number of students who took the SAT in 1992 because they couldn’t hack into the computer and record an 800?
    • A. 250,000
    • B. 140,000
    • C. 120,000
    • D. 100,000

The answer is Choice (C). In 1994, “Grandparents won’t donate a building” accounted for 40 percent of test-taking reasons (from 20 to 60). Because 1994 had 350,000 test-takers, multiply

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In 1992, “Couldn’t hack into computer and record an 800” counted for 20 percent of test-taking reasons (60 to 80). In 1992, 100,000 students took the test. Multiply

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The correct answer is 140,000 – 20,000 = 120,000, or Choice (C).