During a Thanksgiving weekend, a car rental company rented six-tenths of their vehicles, including two-fifths of the 4WDs that it had. If 60% of the vehicles are 4WDs, then what percent of the vehicles that were not rented were not 4WDs?	Choose one.
A) 10%
B) 15%
C) 20%
D) 25%
E) 30%
4/10 of all the vehicles were not rented.   (3/5)(3/5) = 9/25 of all the vehicles are 4WDs that were not rented.   (9/25) / (4/10) = 9/10 is the fraction of non-rented vehicles that were 4WDs   1 - 9/10 = 10% of non-rented vehicles were not 4WDs.   The answer is 10%.
<result>A</result>
During a Thanksgiving weekend, a car rental company rented six-tenths of their vehicles, including two-fifths of the 4WDs that it had. If 60% of the vehicles are 4WDs, then what percent of the vehicles that were not rented were not 4WDs?