a motorboat travels 96km in three hours going upstream it travels 160km going downstream in the same amount of time. what is the rate of the boat in still water

Respuesta :

Answer:

The speed of motorboat in still water = 42.67 km / h

Explanation:

Let speed of motorboat = u

     speed of current = v

Then upstream speed = u - v

Negative  sign is due to that the current and motorboat directions are opposite.

And downstream speed = u + v

Distance traveled by motorboat in upstream = 96 km

Time taken = 3 hours

Then upstream speed (u - v) = [tex]\frac{96}{3}[/tex] = 32 km / h ---------------- (1)

Distance traveled by motorboat in downstream = 160 km

Time taken = 3 hours

Downstream speed (u - v) = [tex]\frac{160}{3}[/tex] km / h =  53.34 km / h -------------------------- (2)

By adding equations (1) & (2), we get

⇒ 2 u = 32 + 53.34

⇒ 2 u = 85.34

⇒ u = [tex]\frac{85.34}{2}[/tex]

⇒ u = 42.67 km / h

Thus the speed of motorboat in still water = 42.67 km / h