<PRE><B>Question 593119</B>
on a 100km track, a train travels the first 25 km at a uniform speed of 35km/hr.How fast the train could travel over the next 75 km so as to give an average speed of 50km/hr for the entire trip
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d = r*t
t = d/r
t1 = 25/35 hours
Total time = 100/50 = 2 hours
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time to travel 75 km = 2 hrs - 5/7 = 9/7 hours
r = d/t
r = 75/(9/7) = 525/9  = 175/3 km/hr
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