A motorboat takes 5 hours to travel 100mi going upstream. The return trip takes 2

going-downstream

#1

A motorboat takes 5 hours to travel 100mi going upstream. The return trip takes 2
hours going downstream. What is the rate of the boat in still water and what is the rate of the current? Rate of the boat in still water: __ mi/h Rate of the current: __ mi/h

Answer:

let , boat speed in still water = v mi/h
and current speed = r mi/h
so,100 = 5(v-r)
v-r =20…(i)
100 = 2(v+r)
v+r =50…(ii)
now, adding (i) and (ii)
boat speed in still water (v) = 35 mi/h
current speed ® = 15 mi/h