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Mathematics>Standard Multiple Choice

Read the following SAT test question and then click on a button to select your answer.

Every student who studies art in a certain school receives exactly one of the grades A, B, C, or D. If 1/5 of the students receive A's, 1/4 receive B's, 1/2 receive C's, and 10 students receive D's, how many students in the school study art?

(A) 30
(B) 60
(C) 100
(D) 200
(E) 500

答案和解析

答案：D

解析：

The students who receive A's, B's, and C's account for (1/5) + (1/4) + (1/2) of the students, that is, 19/20. This leaves 1/20 of the students receiving D's. You know that 10 students receive D's, so 10 is 1/20 of the total. This means that the total number of students is 10 times 20, or 200.