Jack and Jill are marathon runners. Jack can finish a marathon (41 km) in 4.5 hours and Jill can run a marathon in 4.1 hours.What is the ratio of their average running speed? (Jack: Jill)	Choose the correct choice from the following options:
A) 41 / 45  B) 15 / 14  C) 4 / 5  D) 5 / 4  E) can not be determined

Rationale: "average speed of jack = distance / time = 41 / ( 9 / 2 ) = 82 / 9 average speed of jill = 41 / ( 4.1 ) = 10 ratio of average speed of jack to jill = ( 82 / 9 ) / 10 = 82 / 90 = 41 / 45 answer a"
Answer: A