document.write( "Question 713149: Suppose a boat has a speed in still water of 10 mph. The boat travels 48 miles upstream and then makes the 48 mile trip downstream, in a total travel time of 10 hours. What is the speed of the river? - (I don't know how to put the info into a table or how to write the equation that would help me figure this out) \n" ); document.write( "
Algebra.Com's Answer #438355 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
Suppose a boat has a speed in still water of 10 mph.
\n" ); document.write( " The boat travels 48 miles upstream and then makes the 48 mile trip downstream, in a total travel time of 10 hours.
\n" ); document.write( " What is the speed of the river? -
\n" ); document.write( ":
\n" ); document.write( "Let x = the speed of the river
\n" ); document.write( "then
\n" ); document.write( "(10-x) = effective speed upstream
\n" ); document.write( "and
\n" ); document.write( "(10+x) = effective speed downstream
\n" ); document.write( ":
\n" ); document.write( "Write a time equation; time = dist/speed
\n" ); document.write( ":
\n" ); document.write( "upstr time + downstr time = 10 hrs
\n" ); document.write( "\"48%2F%28%2810-x%29%29\" + \"48%2F%28%2810%2Bx%29%29\" = 10
\n" ); document.write( "multiply by (10-x)(10+x) to clear the denominators, results
\n" ); document.write( "48(10+x) + 48(10-x) = 10(10-x)(10+x)
\n" ); document.write( "480 + 48x + 480 - 48x = 10(100 - x^2)
\n" ); document.write( "960 = 1000 - 10x^2
\n" ); document.write( "10x^2 = 1000 - 960
\n" ); document.write( "10x^2 = 40
\n" ); document.write( "x^2 = 4
\n" ); document.write( "x = 2 is the speed of the river
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "See if that checks out, find the actual time each way.
\n" ); document.write( "48/8 = 6
\n" ); document.write( "48/12 = 4
\n" ); document.write( "-----------
\n" ); document.write( "tot time 10 hr \n" ); document.write( "
\n" );