Jack and Jill are marathon runners. Jack can finish a marathon (40 km) in 4.5 hours and Jill can run a marathon in 4.0 hours.What is the ratio of their average running speed? (Jack: Jill)	Choose one.
A) 14/15
B) 15/14
C) 8/9
D) 5/4
E) Cannot be determined
Average Speed of Jack =Distance/ Time   = 40 /(9/2) = 80/9   Average Speed of Jill = 40/(4.0)= 
<gadget id="calculator">40/(4.0)</gadget>
<output>10</output>
10   Ratio of Average speed of Jack to Jill= (80/9)/10 = 8/9   Answer 8/9
<result>C</result>
Jack and Jill are marathon runners. Jack can finish a marathon (40 km) in 4.5 hours and Jill can run a marathon in 4.0 hours.What is the ratio of their average running speed? (Jack: Jill)