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's trip

Answer 1

hey friend here is your ans-

let distance ne 's'
speed while travelling for the trip = 20km/h

s = d/t1
20 = s/t1
t1 = s/20 km/h

speed on return= 30km/h
speed= s/t2
30 = s/t2
t2= s/30

Total distance= s+s km
=2s km
Total time= s/20+s/30
= 3s+2s/60
=5s/60 ans.

hope this helps you...
best of luck for your studies..

Answer 2

$= let \: the \:distance \: travel \\ = x + x = 2x \\ total \: time \: taken \: \\ = x \div 20 + x \div 30 \\ = (3 x + 2x) \: \div 60 \\ \\ = 5x \div 60 \\ avg \: speed \: = \\ distance \div time \: \\ = 2x \div 5x \div 60 \\ = 120x \div 5x \\ = 24$