Each member of a research group visited either the Virgin
Islands or Hawaii. If 8 members went to the Virgin Islands, 13 went to Hawaii,
and 3 went to both locations, how many researchers were in the group?
A. 13
B. 15
C. 18
D. 21
E.
24
The correct answer is choice (C).
Write out the information you were given:
Researchers who went to the Virgin Islands: 8
Researchers who went to Hawaii: 13
Researchers who went to both places: 3
The number of researchers who went to the Virgin Islands
plus the number of researchers who went to Hawaii is 8 + 13, or 21.
In this tally, the three researchers who went to both
places have been counted twice, so subtract 3 from the total: 21 - 3 = 18.
So, there were 18 researchers in the group.
