<PRE><B>Question 718611</B>
 a car travelled at 60km/h for 2 1/2h. during the next 2h it travelled at 56km/h. for the last 1 1/2h of the journey it travelled at 50km/h. 
calculate the average speed of the car during the whole journey.
:
Find the total distance of the journey
60 * 2.5 = 150 km
56 * 2.0 = 112 km
50 * 1.5 =  75 km
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total dist: 337 km
:
Find the total time taken for the journey
2.5 + 2 + 1.5 = 6 hrs
:
Average speed = dist/time
av = 337/6
av = 56.167 km/hr</PRE>