In a group of 15 , 7 have studied Latin , 8 have studied Greek, and 3 have not studied either . How many of these studied both Latin and Greek ?
A
3
B
4
C
5
Correct Answer: 3
( 7 - x) + x + ( 8 - x) + 3 = 15 18 - x = 15 x = 18 - 15 x = 3