how many over 40 have master's degrees?

vittalgmat 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 forty have master’s degrees?

(1) Exactly 100 of the employees are college graduates.

(2) Of the employees forty years old or less, 25 percent have master’s degrees.

OA after some discussion.

60% of the employees are old (over 40 ) and 30% of the old people have masters degrees. So, we know that 18% (30% of 60%) of the employees have masters degrees. So, it would be useful to know the total number of employees.

(1) 100 of the employees are college graduates. We also know that 50% (half) of the employees are college graduates. So, we can conclude that there are 200 employees.
Since 18% of the employees have masters degrees, we can conclude that 36 employees have masters degrees. SUFFICIENT
(2) This just provides us with an additional percentage. The original question asks us for the number of employees with masters degrees. At the moment all of our information is provided as percents, so this is INSUFFICIENT.

Answer: A