Question 1137613
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Here are two different ways to set up the problem that lead to different forms of the same proportion that leads to the answer to the problem.<br>
Let b be the boat's speed; then b+8 is the downstream speed and b-8 is the upstream speed.<br>
(1) Time = distance / rate.  Write and solve the proportion that says the times are the same:<br>
{{{16/(b+8) = 6/(b-8)}}}<br>
(2) Write and solve the proportion that says the ratio of speeds is the same as the ratio of distances, because the times are the same:<br>
{{{(b+8)/(b-8) = 16/6}}}<br>
It should be clear that the two proportions are equivalent and so will lead to the same answer.<br>
Try both methods for setting up the problem; then if you encounter more problems like this, use the method you find is easier for you.