An immigration agent sampled cars going from country M to country N. In his report, he indicated that of the 85 cars sampled, 27 cars were driven by women, 53 cars were driven by citizens of country M, 41 cars had two or more passengers, 23 cars were driven by women who are citizens of country M, 22 cars were driven by women and had two or more passengers, 18 cars were driven by citizens of country M and had two or more passengers, and 13 cars were driven by women who are citizens of country M 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 agent's report contained an error.