document.write( "Question 1134504: A boat travels at 16 mph in still water. It takes the same amount of time for the boat to travel 15mi downstream as to go 9 mi upstream. Find the speed of the current. \n" ); document.write( "

Algebra.Com's Answer #751926 by greenestamps(13200) $\"\"$ $\"About$

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\n" ); document.write( "If the times are the same, then the ratio of distances is the same as the ratio of speeds.

\n" ); document.write( "Let c be the speed (mph) of the current. Since the boat's speed in still water is 16, the upstream and downstream speeds are 16-c and 16+c. Then, since the boat can go 15mi downstream in the same time is can go 9mi upstream,

\n" ); document.write( " $\"%2816%2Bc%29%2F%2816-c%29+=+15%2F9+=+5%2F3\"$
\n" ); document.write( " $\"80-5c+=+48%2B3c\"$
\n" ); document.write( " $\"32+=+8c\"$
\n" ); document.write( " $\"c+=+4\"$

\n" ); document.write( "The speed of the current is 4mph. \n" ); document.write( "

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