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There are 20 students in the class, four of them are being tested by the teacher. How many options are there to choose who the teacher will test?
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Math student
What does this question mean? Don't all the students take all the exams?
It would make more sense if the question said: There are 20 students in the class, and every day four of them go to the library. After how many days will all possible sets of 4 students have gone to the library together, assuming the same 4 never go together twice?
It would make more sense if the question said: There are 20 students in the class, and every day four of them go to the library. After how many days will all possible sets of 4 students have gone to the library together, assuming the same 4 never go together twice?
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