SAT备考数学练习题（1）

sat考试官方网站每日一题小结，以下是SAT数学部分。

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

The bar graph above shows the number of employees at Company X for each of the years from 1996 through 2000. Over which of the following periods was the average rate of increase in the number of employees at Company X greatest?

From 1996 through 1998

From 1996 through 1999

From 1997 through 1999

From 1998 through 1999

From 1998 through 2000

Correct Answer: D

Here"s Why:

You can estimate the rate of increase for each of the five choices to find which is the greatest.

From 1996 through 1998, Company X gained roughly 20 employees over 2 years, for an average rate of increase of about 10 employees per year.

From 1996 through 1999, Company X gained roughly 75 employees over 3 years, for an average rate of increase of about 25 employees per year.

From 1997 through 1999, Company X gained roughly 65 employees over 2 years, for an average rate of increase of about 32 employees per year.

From 1998 through 1999, Company X gained roughly 55 employees over 1 year, for a rate of increase of about 55 employees per year.

From 1998 through 2000, Company X gained roughly 30 employees over 2 years, for an average rate of increase of about 15 employees per year.

Of the choices, the average rate of increase in the number of employees at Company X was greatest for the period from 1998 through 1999.

There is also a quicker way to figure out the answer. Choice D, from 1998 through 1999, is the single largest yearly increase in the number of employees. Therefore, the average rate of increase for any other time period must be less than that for this 1-year period.

Difficulty: Medium

Question Type: Standard Multiple Choice