BTGmoderatorLU wrote:In a certain office, 50 percent of the employees are college graduates and 60 percent of the employees are over 40 years old. If 30 percent of those over 40 have master's degrees, how many of the employees over 40 have master's degrees?

(1) Exactly 100 of the employees are college graduates.
(2) Of the employees 40 years old or less, 25 percent have master's degrees.

Let T = the total number of employees.
Since 60% of the employees are over 40, we get:
Over 40 = 0.6T
30% of those over 40 -- in other words, 30% of the expression in blue -- have master's degrees.
Thus:
Over 40 with master's = 0.3(0.6T).

To calculate the value of the expression in red, we need to know the value of T.
Question stem, rephrased:
What is the value of T?

Statement 1:
Since the 100 college graduates constitute 50% of the total number of employees, T=200.
SUFFICIENT.

Statement 2:
Here, the information given by the prompt and the statement is constrained to PERCENTS.
Since no actual values are given, the value of T cannot be determined.
INSUFFICIENT.

The correct answer is A.

I have a question. The stem talks about college graduates and then later mentions master's degrees. Initially, I was a bit concerned about if it is a three-set problem -- college graduates - masters and non-masters with age. How can we safely assume that college graduates mean only those with masters? That makes the problem simpler of course. Any thoughts?

We cannot assume that every college graduate also has a master's degree.
It is certainly possible to be a college graduate without a master's degree.