document.write( "Question 67295This question is from textbook An Incremental Development
\n" ); document.write( ": The current in the river flowed at 3 miles per hour. The boat could travel 24 miles downstream in one-half the time it took to travel 12 miles upstream. What was the speed of the boat in still water? \n" ); document.write( "
Algebra.Com's Answer #47902 by ankor@dixie-net.com(22740)\"\" \"About 
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The current in the river flowed at 3 miles per hour. The boat could travel 24 miles downstream in one-half the time it took to travel 12 miles upstream. What was the speed of the boat in still water?
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\n" ); document.write( "Let s = speed in still water
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\n" ); document.write( "Speed upstream: (s-3)
\n" ); document.write( "Speed downstream: (2+3)
\n" ); document.write( ":
\n" ); document.write( "Write a time equation: time = dist/speed
\n" ); document.write( ":
\n" ); document.write( "Time 24 mi downstream = half the time 12 mi upstream
\n" ); document.write( "\"24%2F%28%28s%2B3%29%29\" = \".5%2812%2F%28%28s-3%29%29%29\"
\n" ); document.write( ":
\n" ); document.write( "\"24%2F%28%28s%2B3%29%29\" = \"6%2F%28%28s-3%29%29\"
\n" ); document.write( ":
\n" ); document.write( "Cross multiply:
\n" ); document.write( "24(s-3) = 6(s+3)
\n" ); document.write( "24s - 72 = 6s + 18
\n" ); document.write( "24s - 6s = 18 + 72
\n" ); document.write( "18s = 90
\n" ); document.write( "s = 90/18
\n" ); document.write( "s = 5 mph in still water
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\n" ); document.write( "Check:
\n" ); document.write( "24/8 = 3hr for 24 mi downstream
\n" ); document.write( "12/2 = 6hr for 12 mi upstream \n" ); document.write( "
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