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CBSE Class 9 Answered

A Car coves 30km at a uniform speed of 30km/hr.What should be its speed for the next 90km if the average speed for entire journey is 60km/hr ?
Asked by bcnandi | 23 Sep, 2018, 01:08: PM
answered-by-expert Expert Answer
Total distance = 30+90 =120 km.
 
first 30 km is covered by speed 30 km/hr. hence time for first 30 km = distance/speed = 30 km/(30 km/hr) = 1 hour
 
time taken for total trave of 120 km with average speed 60 km/hr = 120/60 = 2 hour.
 
In this total time 2 hour, 30 km is travelled in  first 1 hour.
 
hence required speed for remaining 60 km in remaining time 1 hour is 60 km/hr
Answered by Thiyagarajan K | 23 Sep, 2018, 02:41: PM

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