SOLUTION: the distance between two towns P and Q is 120 km. A car travelled from P to Q at an average speed of 80km/h. On its return journey, the time taken was 30 minutes shorter. Calculate

Question 327936: the distance between two towns P and Q is 120 km. A car travelled from P to Q at an average speed of 80km/h. On its return journey, the time taken was 30 minutes shorter. Calculate its average speed for the whole journey
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
distance between P & q =120 km
speed = 80km/h
time taken = 120/80= 4/3 hours
..
return trip took 4/3 - 1/2 hour =5/6 hours
speed = 120/(5/6)
=120*6/5
=24*6
=144km/hour
Average speed = Total distance / total time
=120+120 / (4/3+5/6)
240/(8+5/6)
240*6/13
=1440/13
=110.7 km/hr average speed
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