Question
There were 30 students in a class. 20 of them got an A in a Chinese test. 17 of them got an A in a History test. Every student got at least an A in the Chinese test or History test. How many of them got an A in both the Chinese and History tests?
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There were 30 students in a class. 20 of them got an A in a Chinese test. 17 of them got an A in a History test. Every student got at least an A in the Chinese test or History test. How many of them got an A in both the Chinese and History tests?