document.write( "Question 349630: Robert has a jet ski that will travel at the rate of 35 mph in still water. He can go 50 mph up a river in the same amount of time it takes im to go 75 mph down the river. How fast can Robert travel going down the river? \n" ); document.write( "

Algebra.Com's Answer #249962 by ewatrrr(24785) $\"\"$ $\"About$

You can put this solution on YOUR website!
Hi,
\n" ); document.write( "*Note: d= r*t t= d/r\r
\n" ); document.write( "\n" ); document.write( ".
\n" ); document.write( "time is the same up and down the river
\n" ); document.write( " $\"50mi%2F%2835+-c%29+=+75mi%2F%2835%2Bc%29\"$
\n" ); document.write( ".
\n" ); document.write( "Cross multiply to solve
\n" ); document.write( "75*(35 -c) = 50*(35+c)
\n" ); document.write( ".
\n" ); document.write( "divide both sides of the equation by 25
\n" ); document.write( "3(35-c) = 2*(35+c)
\n" ); document.write( "105 - 3c = 70 +2c
\n" ); document.write( "35 = 5c
\n" ); document.write( "c = 7(mi/hr)
\n" ); document.write( ".
\n" ); document.write( "Speed going down the river is 35(mi/hr) + 7(mi/hr)= 42(mi/hr)
\n" ); document.write( ".
\n" ); document.write( "check your answer
\n" ); document.write( "50/28 = 75/42 \n" ); document.write( "

\n" );