Last Updated on May 11, 2023
GMAT OFFICIAL GUIDE DS
Solution:
We have a group of 50 people and need to determine how many of those people are doctors with a law degree.
We can use the following formula:
total = # of doctors + # of lawyers – # both + # neither
50 = # of doctors + # of lawyers – # both + # neither
Statement One Alone:
In the group, 36 people are doctors.
So, we have:
50 = 36 + # of lawyers – # both + # neither
24 = # of lawyers – # both + # neither
We cannot determine the number of people who are both. Statement one alone is not sufficient to answer the question.
Statement Two Alone:
In the group, 18 people have a law degree.
So, we have:
50 = # of doctors + 18 – # both + # neither
32 = # of doctors – # both + # neither
We cannot determine the number of people who are both. Statement two alone is not sufficient to answer the question.
Statements One and Two Together:
Using statements one and two, we have:
50 = 36 + 18 – # both + # neither
-4 = – # both + # neither
# both = 4 + # neither
We still cannot determine the number of “both” since we don’t know the number of “neither.”
Answer: E
