SAT数学真题对于大家是最好的备考SAT数学的材料，所以大家一定要对SAT数学真题中的题目都进行认真的解答和详细的分析。下面就为大家提供了一道SAT数学真题及其答案，供大家参考，希望对大家有所帮助。

A special lottery is to be held to select the student who will live in the only deluxe room in a dormitory. There are 100seniors, 150juniors, and 200sophomores who applied. Each senior's name is placed in the lottery 3times; each junior's name, 2　　times; and each sophomore's name,1time. What is the probability that a senior's name will be chosen?

Answer Choices

(A)1 over 8

(B)2 over 9

(C)2 over 7

(D)3 over 8

(E)1 over 2

The correct answer is D

Explanation

Difficulty: Hard

To determine the probability that a senior's name will be chosen, you must determine the total number of seniors' names that are in the lottery and divide this number by the total number of names in the lottery. Since each senior's name is placed in the lottery3　　times, there are3 times 100 = 300seniors' names. Likewise, there are2 times 150 = 300juniors' names and1 times 200 = 200sophomores' names in the lottery. The probability that a senior's name will be chosen is300 over (300 + 300 + 200) = 300 over 800 = 3 over 8.