jack and jill are marathon runners. jack can finish a marathon ( 42 km ) in 3.5 hours and jill can run a marathon in 4.2 hours. what is the ratio of their average running speed? ( jack: jill )	Choose one:
A) 14 / 15  B) 15 / 14  C) 4 / 5  D) 6 / 5  E) can not be determined
<gadget id="calculator">42 / 3.5</gadget>
<output>12</output>

<gadget id="calculator">42 / 4.2</gadget>
<output>10</output>

<gadget id="calculator">12 / 10</gadget>
<output>6/5 = around 1.2</output>

<result>D</result>
jack and jill are marathon runners. jack can finish a marathon ( 42 km ) in 3.5 hours and jill can run a marathon in 4.2 hours. what is the ratio of their average running speed? ( jack: jill )
divide(divide(42, 3.5), divide(42, 4.2))
average speed of jack = distance / time = 42 / ( 7 / 2 ) = 84 / 7 average speed of jill = 42 / ( 4.2 ) = 10 ratio of average speed of jack to jill = ( 84 / 7 ) / 10 = 84 / 70 = 6 / 5 answer d