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Mathematics>Standard Multiple Choice

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

The graph at left models the monthly bill, m, in dollars, that a particular video hosting company charges a customer who uses t terabytes of bandwidth. What is the best interpretation of the average rate of change between 10 and 35 terabytes in this context?

(A) The average amount the company charges each month is about $ 91 per terabyte up to the tenth terabyte.
(B) The average amount the company charges each month is about $ 110 per terabyte up to the tenth terabyte.
(C) The average amount the company charges each month is about $ 91 per terabyte after the tenth terabyte but before the thirty-fifth.
(D) The average amount the company charges each month is about $ 110 per terabyte after the tenth terabyte but before the thirty-fifth.

答案和解析

答案：C

解析：

Choice C is correct. The average rate of change between two points is the same as the slope of a line connecting these 2 points in a graph.