Question 215864
Delmas flew to Detroit in 90 minutes and drove his car back home in 6 hours. If he drove 150mph slower than he flew, then how fast did he fly?


Step 1.  Let x be the speed of the plane.


Step 2.  Let x-150 be the speed of the car.


Step 3.  Let 1.5x be the distance flew by plane where 90 minutes=1.5 hours and 60 minutes = 1 hour.


Step 4.  Let 6(x-150) be the distance drove by car.


Step 5.  Distances traveled by plane and car means setting equations in Steps 3 and 4 to be equal.


{{{1.5x=6(x-150)}}}


*[invoke explain_simplification "1.5x=6(x-150)" ]

With x=200, then x-150=50.  


Check if distances are equal...  1.5*200=6*50 or 300=300 a true statement


Step 6.  The speed of the plane is 200 mph.



I hope the above steps were helpful.


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Good luck in your studies!


Respectfully,
Dr J