Problema Solution
A man drove his car from his home to a friend's house at a speed of 64 km/h and it took him 20 minutes. When he returned to his home he travelled along the same roads but at a speed of 80 km/h. How long did the return trip take?
Answer provided by our tutors
v1 = 46 km/h
t1 = 20 min
t1 = 20/60 h
t1 = 1/3 h
v2 = 80 km/h
t2 = the time man traveled with speed v2 = 80 km/h
Since speed = distance/time follows distance = speed*time:
v1*t1 = v2*t2
46*(1/3) = 80*t2
80*t2 = 46/3
t2 = 46/(3*80) h
t2 = 60*(46/(3*80)) min (since 1 h = 60 min)
t2 = 11.5 min
The return trip took him 11.5 minutes.