Find the speed of the tugboat without a current and the speed of the current.
The speed of the tugboat is what in mph? And what is the speed of the current in mph? (Simplify your answer.)
Let x be the speed of tugboat without a current and y be the speed of the current.
Upstream speed is "x-y" (because of the stream resistance) and the downstrean speed is "x+y" (the stream helps to move faster). According to the text
20(x-y) = 160
10(x+y) = 160
Simplify the system of these two equations dividing both sides of the firsdt equation by 20 and the second one by 10. We will obtain
x-y = 8
x + y = 16
Addition of two equations gives 2x = 24 or x =12. Consequently y = 12 - 8 = 4 or 16-12 =4.
Summarize: x= 12 y = 4.