one fourth of a journey is covered at a rate of 50 km per hour, 1 3rd 60 kilometre per hour and the rest of the rate of 100 kilometre per hour full stop find the average speed for the whole journey
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Answer:
67.92
Step-by-step explanation:
let total distance be
= L.C.M (4,3 ) = 12 km
dis. covered at 50km/h
= 1/4 * 12 = 3 km
at 60km/h = 1/3* 12 = 4km
at 100km/h = 12 - (3+4) = 5km
total time taken
= 3/50 + 4/60 + 5/100
= 3/50 + 1/15 + 1/20
= (3×6 + 1 × 20 + 15 )/300
=53/300
average speed = 12/53/300
= 3600/53 = 67.92 km/hr
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