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Mathematics>Standard Multiple Choice

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

In the figure above, the length of line A B is 2x and the length of line B C is 3x. If a point is chosen at random from line A C, what is the probability that the point will lie on line B C?

(A) 2/5
(B) 1/2
(C) 3/5
(D) 2/3
(E) 5/6

答案和解析

答案：C

解析：

The probability that a point chosen from line A C will lie on line B C is the ratio of the length of line B C to the length of line A C. The length of line A B is 2x and the length of line B C is 3x, so the length of line A C is 5x. Therefore, the ratio of the length of line B C to the length of line A C is (3x)/(5x) = 3/5.