Question

one third of a journey is covered at the rate of 25 km per hour one fourth at the rate of 30 Km per hour and rest at the rate of 50 Km per hour find the average speed for the whole journey​

Answer 1

=> D = Total Distance

=> T = Total Time

=> D/3 at 25

=> D/4 at 30

=> 5d/12 at 50

=> T = ( d/3 ) / 25 + ( d/4 ) / 30 + ( 5d/12 ) / 50

=> 150t = 2d + 5d/4 + 5d/4 = 9d/2

=> 300t = 9d

=> T = 3d/100

=> D = 100t/3

=>D/T = rate = 100/3

=> 33 1/3 km/hr

I hope this will help you dear..

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