Bunuel
In a research and development department, 14 workers have a PhD, and 30 workers don't have a PhD degree. In the department, the number of women that do not have a PhD degree is 10 greater than the number of women who do have a PhD. If a third of the men working in the department have a PhD degree, then how many women work in the department?
A) 16
B) 18
C) 26
D) 28
E) 32
Let's use the
Double Matrix Method.
This technique can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions)..
Here, we have a population of workers, and the two characteristics are:
- has a PhD or doesn't have a PhD
- woman or man
In a research and development department, 14 workers have a PhD, and 30 workers don't have a PhD degree.So there are 44 workers in TOTAL.
Our diagram looks like this:
In the department, the number of women that do not have a PhD degree is 10 greater than the number of women who do have a PhD.Let x = the number of women who DO have a PhD degree is 10 greater
So, x+10 = the number of women who do NOT have a PhD degree is 10 greater
We can add this information to the diagram to get:
A third of the men working in the department have a PhD degreeLet y = the total number of men working in the department
So, y/3 = the number of men WITH a PhD degree
And 2y/3 = the number of men WITHOUT a PhD degree
We get:
How many women work in the department?On the left-side column, we see that: x + y/3 = 14
Multiply both sides by 3 to get:
3x + y = 42On the right-side column, we see that: (x + 10) + 2y/3 = 30
Simplify to get: x + 2y/3 = 20
Multiply both sides by 3 to get:
3x + 2y = 60We have:
3x + 2y = 603x + y = 42Subtract the bottom equation from the top equation to get: y = 18
This means there are 18 MEN in the department.
Since there are 44 workers in total,
the remaining 26 workers are WOMENAnswer: C
This question type is
VERY COMMON on the GMAT, so be sure to master the technique.
To learn more about the Double Matrix Method, watch this video:
EXTRA PRACTICE QUESTION
More questions to practice with:
EASY:
https://gmatclub.com/forum/of-the-120-p ... 15386.html MEDIUM:
https://gmatclub.com/forum/in-a-certain ... 21716.html HARD:
https://gmatclub.com/forum/a-group-of-2 ... 24888.html KILLER:
https://gmatclub.com/forum/a-certain-hi ... 32899.html