How many multiples of 5 are there between 50 and 500 ?  Answers
A) 128	B) 91	C) 89	D) 61	E) 60

Rationale: "it should be mentioned whether 50 and 500 are inclusive . if 50 and 500 are inclusive , then the answer is ( 500 - 50 ) / 5 + 1 = 91 . if 50 and 500 are not inclusive , then the answer is ( 495 - 55 ) / 5 + 1 = 89 . since oa is c , then we have not inclusive case ."
Answer: C