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Mathematics>Standard Multiple Choice

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

There are n students in a biology class, and only 6 of them are seniors. If 7 juniors are added to the class, how many students in the class will not be seniors?

(A) n-3
(B) n-2
(C) n-1
(D) n+1
(E) n+2

答案和解析

答案：D

解析：

At first, there are n students in the class, and 6 of them are seniors. It follows that initially n-6 students are not seniors. If 7 juniors are added to the class, there will be n-6 + 7, or n+1, students in the class who are not seniors.