Question 1129303
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There are so many types of problems like this that it might be worthwhile to look at a quick way to solve them without formal algebra... if, of course, a formal algebraic solution is not required.<br>
You have a downstream speed of 80/5 = 16mph, which is the speed of the current added to the speed of the boat; you have an upstream speed of 80/8 = 10mph, which is the speed of the current subtracted from the speed of the boat.<br>
Common sense (or a bit of visualization on a number line) says that the speed of the boat is halfway between those two speeds; and then the speed of the current is the difference between the speed of the boat and either the upstream or downstream speed.<br>
In this problem....<br>
The boat's speed is (16+10)/2 = 13mph;
The speed of the current is 16-13 = 3mph (or 13-10 = 3mph).<br>
You are doing exactly the same calculations as with formal algebra; but you aren't slowed down by writing and solving equations.