Discovering an Error An immigration agent sampled cars

Chapter 2, Problem 2.1.383

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Discovering an Error An immigration agent sampled cars going from the United States into Canada. In his report, he indicated that of the 85 cars sampled, 35 cars were driven by women. 53 cars were driven by U.S. citizens. 43 cars had two or more passengers. 27 cars were driven by women who are U.S. citizens. 25 cars were driven by women and had two or more passengers. 20 cars were driven by U.S. citizens and had two or more passengers. 15 cars were driven by women who are U.S. citizens and had two or more passengers. After his supervisor reads the report, she explains to the agent that he made a mistake. Explain how his supervisor knew that the agents report contained an error.