Question 1105322: Help me to solve this problem: A plane takes 10 hours less to travel 1200 km than a train. If the plane travels six times as fast as
the train, what was the speed of the plane? Answer is Speed of the train was 100 km/hr, the plane was 600 km/hr.
Found 3 solutions by Alan3354, josgarithmetic, ikleyn:
Answer by Alan3354(69443)   (Show Source):
Answer by josgarithmetic(39613)  (Show Source):
You can put this solution on YOUR website! -----------------------------------------------------------------------------
A plane takes 10 hours less to travel 1200 km than a train. If the plane travels six times as fast as
the train, what was the speed of the plane?
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Easier to assign variables as shown here:
SPEED TIME DISTANCE
PLANE 6r 1200/(6r) 1200
TRAIN r 1200/r 1200
DIFFERENCE 10
You are really asked to find 6r but you can solve for r first.
Answer by ikleyn(52752)  (Show Source):
You can put this solution on YOUR website! .
The MENTAL solution is also possible:
If the plane travels six times as fast as the train, the train spends six times as long time as the plane:
6x hours for the train and x hours for the plane.
The difference is 10 hours: 6x - x = 10 hours, according to the condition.
Hence, 5x = 10 and x =  = 2 hours.
Having 2 hours for the plane, you momentarily determine its speed:  = 600 km/hours, exactly as in your answer.
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