One night 10 percent of the female officers on a police force were on duty. If 200 officers were on duty that night and half of these were female officers, how many female officers were on the police force?  Select.
A) 90	B) 180	C) 270	D) 500	E) 1,000

Rationale: "let total number of female officers in the police force = f total number of officers on duty on that night = 200 number of female officers on duty on that night = 200 / 2 = 100 ( 10 / 100 ) * f = 100 = > f = 1000 answer e"
Answer: E