Question

Abdul while driving to school computes the average speed for his trip to be 20 km per hour on his return trip along the same route there is less traffic and average speed is 30 km per hour what is the average speed for Abdul strip

Answer 1

Average speed =2×20×30/20+30 =40×30/50 =

= 24km/h Ans

Answer 2

Let, t1 and t2 be the time taken by Abdul to go to school and come back from the school respectively.

Let S be it's distance covered one way, then

$\large\sf\red{t1 = \frac{s}{20} h + t2 = \frac{s}{40} h}$

$\large\sf\red{Total\:time\:taken=t1+t2}$

$\large\sf\red{ \frac{s}{20} + \frac{s}{40} = \frac{2s}{40} h}$

$\large\sf\purple{Total\:distance\:covered=2s}$

$\therefore$$\large\sf\green{Average\:Speed=\frac{2s}{3s} \times 40}$

$\large\sf\green{\frac{80}{3}=26.67km/h}$