GMAT 双部分分析练习题1

From Fall 2010 to Spring 2015, the number of professors at a particular university decreased, while there was an increase in student enrollment from 4,500 students in Fall 2010.

In the given expressions, P and T represent the percent change in the number of professors and students, respectively, over the 5 academic years. The percent change in a quantity Y is calculated using the formula:  Ynew - Yold / Yold  * 100. Z is the number of students per professor in Fall 2010.

Select the expression that represents the number of professors in Fall 2010, and select the expression that represents the number of students per professor in Spring 2015. Make only two selections, one in each column.