Question

A boat takes 2 hrs to travel 8 km abd back in still water lake with water velocity of 4 km/hr,then the time taken for going upstream of 8 km and coming back is

Answer 1

time = distance/velocity
when in the direction of current velocity = 8+4= 12
t1= 8/12 = 2/3 hr
when against the current velocity 8-4 = 4
t2= 8/4 = 2 hr.
total time = 2+ 2/3 = 8/3 hrs. = 2 hrs&40 minutes

so 100 min is the answer