Question 64716
An airline starts off on a trip with all engines running. It is going at a rate of 900 km per hour, after x hours it shuts down one engine and reduces its speed to 700 km per hour. The trip is a total of 3 hours long
How long should the pilot fly before shutting down one engine in order to go a total distance of 2352 in 3 hours.


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900 km/hr DATA:
rate= 900 km/hr; distance = x km ; time= d/r= x/900 hrs
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700 km/hr DATA:
rate= 700 km/hr; distance = "2352-x" km ; time = d/r = (2352-x)/700 hrs
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EQUATION:
time + time = 3 hrs
x/900 + (2352-x)/700 = 3
700x +900(2352-x)=3*900*700
700x+2116800-900x=1890000
-200x=--226800
x=1134 km at 900 km/hr
2352-x=1218 km at 700 km/hr
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Cheers,
Stan H.