Question 487749
An aeroplane flies from A to B at the rate of 500 km / hour and comes back from B to A at the rate of 700 km / hour. The average speed of the aeroplane is 
As the answer given is : 583.33km per hour 
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A to B DATA:
rate = 500 km/hr ; time = x hrs ; distance = 500x km
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B to A DATA:
rate = 700 km/hr ; time = y hrs ; distance 700y km
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Equation:
distance = distance
500x = 700 y
x = (7/5)y
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Average speed = total distance/total time 
= (500x + 700y)/(x+y)
= (500(7y/5)+700y)/(12y/5)
= 1400y/(12y/5)
= 7000/12
= 583 1/3 km/hr
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Cheers,
Stan H.