A boatcovers 64 km upstream in 8 hours and 120 km downstream in 12 hours. Whatis the speed (in m/s)ofthe boat in still water
downstream speed = $$\frac{distance}{time}$$
downstream speed = $$\frac{120}{12}$$
=10km/hr
upstream speed = $$\frac{distance}{time}$$
upstream speed = $$\frac{64}{8}$$
= 8km/hr
Speed of the boat in still water =$$\frac{speed of upstream + speed of downstream}{2}$$
 = $$\frac {10 + 8} {2}$$
 = 9km/hr
Change into m/s
 =$$(9)\times \frac{5}{18}$$ =2.5 m/s
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