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A motorboat travels 180 km in 3 hours going upstream and 504 in 6 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?

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Answer:

Speed of boat x = 84 km/hr

Speed of current = 12 km/hr

Explanation:

Let 'x' be the speed of boat and 'y' be the speed of still water

Upstream speed = x - y and

Downstream speed = x + y

It is given that, A motorboat travels 180 km in 3 hours going upstream and 504 in 6 hours going downstream

Upstream speed = x - y = 180/3 = 60 km/hr

Downstream speed = x + y = 504/6 = 84 km/hr

To find the value of x and y

x + y = 84 ----(1)

x - y = 60 ----(2)

(1) + (2) ⇒

x + y = 84 ----(1)

x - y = 60 ----(2)

2x + 0 = 144

x = 144/2 = 72

x + y = 84

y = 84 - 72 = 12

Therefore speed of boat x = 84 km/hr

Speed of current = 12 km/hr

User Bogdan Gusiev
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