Walkabout 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.
This would be a perfect place for the "grid" (double matrix, table, you-name-it) ... but there is one more characteristic involved than expected, correct?
In this (rare) case our method suggests the following:
Put in the "grid" two of the three characteristics, the ones with "more info"... the third characteristic is dealt "in parallel"... see the grid below!
Now it´s really simple...
\(\left( 1 \right)\,\,5T = 100\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,? = {3 \over {10}}\left( {6T} \right)\,\,\,\,{\rm{unique}}\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,{\rm{SUFF}}.\)
(2) Insufficient: one possible VIABLE BIFURCATION (36 or 18, when T equals 20 or 10) is shown in blue and pink below:
This solution follows the notations and rationale taught in the GMATH method.
Regards,
Fabio.
_________________
Fabio Skilnik ::
GMATH method creator (Math for the GMAT)
Our high-level "quant" preparation starts here:
https://gmath.net