Question 28453: The average speed of a plane is 560 kilometers per hour. How long does it take the plane to travel 140 kilometers? Answer by emmychan(11) (Show Source):
You can put this solution on YOUR website! Since you know that an hour has 60 minutes, you can say that the plane travels 560k in 60 min. (or 560 / 60). You also know that the plane has only traveled 140k and you need to know the min. Use "x" for unknown min. You get the following equation.
(560/60) = (140/x)
Now you can use cross multiplication to solve for "x"
(It helps to write the problem in columns )
If you cross multiply, you get
560x = 60(140)
560x = 8400
Divide both sides by 560
x = 15
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