Question

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 ?​

Answer 1

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

Answer 2

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).