Question

A car travels hundred kilometre distance at a speed of 60 km per hour and returns with a speed of 40 km per hour calculate its average speed for the whole journey with the diagram

Answer 1

Answer:

48 km/hr

Step-by-step explanation:

Distance one side = 100 km

Speed one side = 60 km/h

time taken one side = Distance/speed = 100/60 hr

= (100/60)*60 = 100 mins

Speed return = 40 km/h

time taken one side = Distance/speed = 100/40 hr

= (100/40)*60 = 150 mins

Total time take = 100 + 150 = 250 min

= 250/60 hr

= 25/6 hr

Total distance = 100 + 100 = 200 km

Average speed = 200/(25/6) = 48 km/hr

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cRAZY pRINCE

Answer 2

Distance/speed = 100/60 hr

= (100/60)*60 = 100 mins

Speed return = 40 km/h

time taken one side = Distance/speed = 100/40 hr

= (100/40)*60 = 150 mins

Total time take = 100 + 150 = 250 min

= 250/60 hr

= 25/6 hr

Total distance = 100 + 100 = 200 km

Average speed = 200/(25/6) = 48 km/hr