Between 2008 and 2012, the number of computer science teachers decreased despite a jump in computer science majors from 400 in 2008.

In the given expressions, T and S represent the percent change in the number of teachers and computer science students, respectively, over the four years and R represents the the number of computer science students per teacher in 2008.

Percent change in a quantity X is calculated using the formula

`((X_(recent)- X_(old) ) / X_(old))` * 100.

Select the expression that represents the number of teachers in 2012 and select the expression that represents the number of computer science students per teacher in 2012.