document.write( "Question 83625: a cruise boat travels 84 miles downstream in 2 hours and returns upstream in 6 hours find the rate of the stream \n" ); document.write( "

Algebra.Com's Answer #60139 by josmiceli(19441) $\"\"$ $\"About$

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s = rate of stream
\n" ); document.write( "b = rate of boat
\n" ); document.write( "For downstream:
\n" ); document.write( " $\"d+=+%28b+%2B+s%29%2At\"$
\n" ); document.write( "For upstream:
\n" ); document.write( " $\"d+=+%28b+-+s%29%2At\"$
\n" ); document.write( " $\"84+=+%28b+%2B+s%29%2A2\"$
\n" ); document.write( " $\"84+=+2b+%2B+2s\"$
\n" ); document.write( "--------------------
\n" ); document.write( " $\"84+=+%28b+-+s%29%2A6\"$
\n" ); document.write( " $\"84+=+6b+-+6s\"$
\n" ); document.write( "Multiply the 1st equation by 3
\n" ); document.write( "and add to the second
\n" ); document.write( " $\"252+=+6b+%2B+6s\"$
\n" ); document.write( " $\"84+=+6b+-+6s\"$
\n" ); document.write( " $\"336+=+12b\"$
\n" ); document.write( " $\"b+=+28\"$ This is the speed of the boat in still water in mph
\n" ); document.write( " $\"84+=+2b+%2B+2s\"$
\n" ); document.write( " $\"84+=+2%2A28+%2B+2s\"$
\n" ); document.write( " $\"2s+=+84+-+56\"$
\n" ); document.write( " $\"2s+=+28\"$
\n" ); document.write( " $\"s+=+14\"$ Rate of stream in mph \n" ); document.write( "

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