Jack and Jill are marathon runners. Jack can finish a marathon (42 km) in 2.5 hours and Jill can run a marathon in 4.2 hours.What is the ratio of their average running speed? (Jack: Jill) Answers:
A) 41/25	B) 15/14	C) 4/5	D) 5/4	E) Cannot be determined
41/25verage Speed of Jack =Distance/ Time   = 42 /(5/2) = 84/5   41/25verage Speed of Jill = 42/(4.2)= 
<gadget id="calculator">42/(4.2)</gadget>
<output>10</output>
10   Ratio of 41/25verage speed of Jack to Jill= (84/5)/10 = 84/50 = 41/25   41/25nswer 41/25
<result>A</result>
Jack and Jill are marathon runners. Jack can finish a marathon (42 km) in 2.5 hours and Jill can run a marathon in 4.2 hours.What is the ratio of their average running speed? (Jack: Jill)