Question

Abdul, while driving to school, computers the average speed for his trip to be 20 km h-1. On his return trip along the same route, there is less traffic and the average speed is 40 km h-1. What is the average speed for Abdul's trip?​

Answer 1

Answer:

Hii Here's Your Answer

Explanation:

Let the distance traveled by Abdul from home to school = s km

time taken to reach the school=t1 sec

For Return journey , Abdul cover distance =s km

time=t2 sec

∴ Average speed for forward journey[home - school ] = Total distance/ Total time.

20 km/h =s/t1

∴t1=s/20 h ------eq(1)

Average speed for backward journey[school -home] = Total distance/ Total time.

30 km/h =s/t2

t2=s/30h -----eq(2)

Average distance for entire journey = Total distance/ Total time

                                                        =(s+s)/[s/20 +s/30]

                                                        =2s/s[1/20+1/30]

                                                         =2x20x30/50

                                                          =24 km/hr

Shortcut method : If equal distance are covered with speeds v1 and v2 then average distance=2v1v2/v1+v2

                          = 2x20x30/50

                           =24km/hr

∴ The average speed for Abdul's trip is 24km/h

Hope It Helps

See Ya :)

Answer 2

here is your answer hope it's help you