One night 17 percent of the female officers on a police force were on duty. If 170 police officers were on duty that night and half of these were female officers, how many female officers were on the police force?
Choose the correct choice from the following
A) 400  B) 420  C) 450  D) 480  E) 500

Rationale: let x be the number of female police officers on the police force . the number of female police officers on duty was 85 . 0.17 x = 85 x = 500 the answer is e .
Answer: E