SOLUTION: An airplane flies 235 miles with a constant speed of 564 mph and another 225 miles with a constant speed of 540 mph. How much time in total does it take to travel these distances?

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Question 1128381: An airplane flies 235 miles with a constant speed of 564 mph and another 225 miles with a constant speed of 540 mph. How much time in total does it take to travel these distances?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
235%2F564%2B225%2F540, in hours


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Ratio of distance to time, is speed.
D, distance; unit may be miles;
T, time; unit may be hours
R, "speed"

D%2FT=R, and the uni for R could be MILES per HOUR.

A couple of simple algebra steps:
%28D%2FT%29T=RT
D=RT
D%281%2FR%29=RT%281%2FR%29
D%2FR=T, a formula for time.

Look at the problem description. Two different distances as part of a trip, and each distance at a different speed.

| flies 235 miles with a constant speed of 564 mph |
The amount of time for this was 235%28miles%29%2A%281%2F564%29%28hours%2Fmiles%29=%28235%2F564%29hours.


| and another 225 miles with a constant speed of 540 mph. |
This portion amount of time was %28225%2F540%29hours.


The total amount of time was the sum:

235%2F564%2B225%2F540, in hours;
The rest is basic arithmetic.

Factorizing numerator and denominators completely:
%285%2A47%29%2F%282%2A2%2A3%2A47%29%2B%283%2A3%2A5%2A5%29%2F%282%2A2%2A3%2A3%2A3%2A5%29

Reduce EAch of them:
5%2F12%2B5%2F12

10%2F12

highlight%285%2F6%29highlight%28hour%29

Change into minutes:
%285%2F6%29%2A%2860%28minutes%2Fhour%29%29

highlight%2850%2Aminutes%29