Abdul, while driving to school, computes the average speed for his trip to be 20 km/h. on his return trip along the same route , there is less traffic and the average speed is 40 km/h.what is the average speed for abdula' strip ?
Answers
Answered by
19
Here is Answer
As we know
Speed = Distance /Time
So according to question
Let Distance be X
Dist while going = dist while returning
So time when going = x/20
time when returning = x/40
Total time = x/20+ x/40
Answered by
36
Answer:
26.67 km/h
Explanation:
let the distance between his house and school be s km.
on his trip from home to school,
time taken = s/20 hours
(since time = distance/speed)
on his return trip,
time taken = s/40 hours
therefore, average speed = total distance/total time
average speed=(s+s)/{(s/20)+(s/40)
= (2×s)/{(2×s + s)/40} lcm = 40
= (2×s)×40/(3×s)
= 2×40/3
= 80/3
= 26.67
therefore Abdul's average speed is
26.67 km/h (ans).
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