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Question

A boat travels 50 mph more than 3 times the speed of a fish. If the boat can travel 505 miles in the same amount of time the fish can travel 35 miles, how fast is east going?

Answer 1

Let f = speed of the fish (in mph)

Let b = speed of the boat (in mph)

 

According to the problem statement, the boat travels 50 mph more than 3 times the speed of the fish:

Therefore, b = 3f+50

 

Let t = time it takes to travel a certain distance

 

f x t = 35

t = 35 / f

 

b x t = 505

(3f+50) x t  = 505

(3f+50) x (35/f) = 505

(3f + 50) x 35 = 505 f

105f + 1750 = 505 f

1750 = 400f

 

Fish's speed, f = 4.375 mph

Boat's speed, b = 3f + 50 = 3(4.375) + 50 = 63.125 mph