A motorist travels 160km at 80km/hr and 160km at 100km/hr. What is the average speed of the motorist for this trip?

I need the step by step solution because I didn't listen to ny teacher properly

3 answers

d1 = r*t = 160 km.
80*t = 160.
t1 = 2 hrs.

d2 = r*t = 160 km.
100*t = 160.
t2 = 1.6 hrs.

r(avg.) = (d1+d2)/(t1+t2) = 320/3.6 =
88.9 km/hr.
Am satisfied
When driving at an average speed of 100km /h calculate the time spent on the road for the journey