During a Thanksgiving weekend, a car rental company rented seven-tenths of their vehicles, including two-fifths of the 4WDs that it had. If 40% of the vehicles are 4WDs, then what percent of the vehicles that were not rented were not 4WDs? Options
A) 20%
B) 30%
C) 40%
D) 60%
E) 25%
3/10 of all the vehicles were not rented.   (3/5)(2/5) = 6/25 of all the vehicles are 4WDs that were not rented.   (6/25) / (3/10) = 4/5 is the fraction of non-rented vehicles that were 4WDs   1 - 4/5 = 20% of non-rented vehicles were not 4WDs.   The answer is 20%.
<result>A</result>
During a Thanksgiving weekend, a car rental company rented seven-tenths of their vehicles, including two-fifths of the 4WDs that it had. If 40% of the vehicles are 4WDs, then what percent of the vehicles that were not rented were not 4WDs?