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  is 2x and the length of  is 3x. If a point is chosen at random from , what is the probability that the point will lie on ?

(A) 

(B) 

(C) 

(D) 

(E) 

答案见下一页>>>

The correct answer is C

Explanation

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