alex.gellatly wrote:Of the people who attended a workshop, 60 percent were teachers and some of the teachers were teachers of language arts. What percent of the people who attended the workshop were teachers of language arts?
(1) 200 people attended the workshop.
(2) 72 of the teachers who attended the workshop were not teachers of language arts.
This is an EITHER/OR group problem.
Every attendee EITHER is a teacher OR is not..
Every attendee EITHER works in language arts OR does not.
For an EITHER/OR group problem, use a GROUP GRID (also known as a double-matrix) to organize the data.
Let T = teacher, NT = not a teacher, L = language arts, NL = not language arts.
In the grids below, the entries in any given row or column must add up to the TOTAL of that row or column.
60 percent were teachers.
The following grid is yielded:
Question stem:
What percent of the people who attended the workshop were teachers of language arts?
Rephrased:
In the grid above, what is the value of x/T?
Statement 1: 200 people attended the workshop.
The following grid is yielded:
No way to determine x/T.
INSUFFICIENT.
Statement 2: 72 of the teachers who attended the workshop were not teachers of language arts.
The following grid is yielded:
No way to determine x/T.
INSUFFICIENT.
Statements combined:
The following grid is yielded:
Thus, x/T = 48/200 = 24/100 = 24%.
SUFFICIENT.
The correct answer is
C.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at
[email protected].
Student Review #1
Student Review #2
Student Review #3
