There are 280 doctors and nurses at a hospital. If the ratio of doctors to nurses is 5 to 9, how many nurses are at the hospital?  Select the correct option
A) 165
B) 170
C) 175
D) 180
E) 185

Rationale: the number of nurses at the hospital is ( 9 / 14 ) * 280 = 180 . the answer is d .
Answer: D