Over a period of 5 academic years from fall 1999

[chuperman601]

From GMAT Prep Software:

Over a period of 5 academic years from fall 1999 through spring 2004, the number of faculty at certain college increased despite the decrease in student enrollment from 5,500 students in fall 1999.

In the given expressions, F and S represent the percent change in the number of faculty and students, respectively, over the 5 academic years, and R represents the number of students per faculty member in Fall 1999. The percent change in the quantity X is calculated using the formula:

((Xnew - Xold)/Xold) * 100

Select the expression that represents the number of faculty in fall 1999, and select the expression that represents the number of students per faculty member in spring 2004. Make only 2 selections, one in each column.

Answers are:

Number of Faculty in 1999
Answer = 5500/R

Students Per Faculty Member in Spring 2004
Answer = (100+S)/(100+F)


My question:


My question is I got the solution for "Students Per Faculty Member in Spring 2004" as:

R*((100+S)/(100+F))

The solutions provided also provided the answer as:
R*((100+S)/(100+F))

However, the solutions ignored the "R" and selected the (100+S)/(100+F) part only.

Why did they ignore the "R"? The initial solution I arrived had the "R" but because none of the solutions had that "R", I rejected it and ended up getting stuck.

Thanks,

C

[tim]

this question doesn't appear to be complete. can you please post a screen shot so we can see the full question?

[chuperman601]

Here you go!

Question:
https://dl.dropbox.com/u/51908491/Question.jpg

Answers:
https://dl.dropbox.com/u/51908491/Answers.pdf

Cheers!

[tim]

looks like a simple typo on their part. they probably intended to include R in answer choices D, E, and F..

[nyc917]

Hi,

I am not sure how to solve for part 2 of this question: students per faculty member in Spring 2004. I could not really follow the solution provided by GMAT Prep. Can someone please provide another method to solve this problem? I tried plugging in numbers, but I could not arrive at the correction solution.

The official solution provided took a formulaic approach:

The variable S represents the percent change in the student population from 1999 to 2004. If X2004 represents the student population in Spring 2004 and X1999 represents the student population in Fall 1999, then
S - 100*((X2004-X1999)/X1999)

I didn't follow what the solution was saying. Can we pick a number for F (percent change in the number of faculty), S (percent change in the number of students), R (ratio), and come up with the correction?

Thanks for your help.

[tim]

Picking numbers would actually work on this one. If you plug values in for R, S, and F, and calculate what the new ratio should be, you can then plug R, S, and F into the answers to see which choice(s) match. This approach is essentially the same as what you do when you have variables in the answer choices for a quant problem.

[nyc917]

Picking numbers would actually work on this one. If you plug values in for R, S, and F, and calculate what the new ratio should be, you can then plug R, S, and F into the answers to see which choice(s) match. This approach is essentially the same as what you do when you have variables in the answer choices for a quant problem.

Thanks a lot, Tim.

[tim]

My pleasure!