SOLUTION: A car completes the first part i.e. 50 kms of its journey in 90 minutes. If it has to complete the whole journey with an average speed of 50 km/hr then how much time, it will take

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Question 757534: A car completes the first part i.e. 50 kms of its journey in 90 minutes. If it has to complete the whole journey with an average speed of 50 km/hr then how much time, it will take to complete the second part i.e. 70 kms of its journey?
Found 2 solutions by sachi, Cromlix:
Answer by sachi(548) (Show Source):
You can put this solution on YOUR website!
let it take t hr to complete the second part i.e. 70 kms of its journey
so the total length of the journey=50+70=120 km
& total time=90/60+t=1.5+t hr
so the average speed=120/(1.5+t)
but 120/(1.5+t)=50
or 1.5+t=120/50=2.4
or t=2.4-1.5=0.9hr=54 mins

Answer by Cromlix(4381) (Show Source):
You can put this solution on YOUR website!
50 kms in 90 mins = ave speed of 33.3 kmph
Total of kms = 120 kms
120 kms/x = 50 kmph
Cross multiply
x = 120 kms/50 kmph = 2.4 hours
2.4 hours = 2hours 24mins.
2 hours 24 mins. - 90 mins
= 54 mins.
This is the amount of time
required to complete 70kms
to achieve an overall average
speed of 50 km/hr.
Hope this helps.
:-)