document.write( "Question 635052: A tugboat goes 120 miles upstream in 20 hours. The return trip downstream takes 5 hours. Find the speed of the tug boat without a current , and with a current. \n" ); document.write( "
Algebra.Com's Answer #400056 by Maths68(1474)![]() ![]() You can put this solution on YOUR website! \r \n" ); document.write( "\n" ); document.write( "Speed of boat without current \n" ); document.write( "---------------------------------- \n" ); document.write( "Time=t=20 hours \n" ); document.write( "Speed of boat= s = \n" ); document.write( "Distance = d = 120 miles \n" ); document.write( "Speed of current = c \n" ); document.write( "Distance=(Speed of boat - Speed of current) *time \n" ); document.write( "120=(s-c)*20 \n" ); document.write( "120/20=s-c \n" ); document.write( "6=s-c \n" ); document.write( "s-c=6………………………….(1)\r \n" ); document.write( "\n" ); document.write( "Speed of boat with the current \n" ); document.write( "---------------------------------- \n" ); document.write( "Time=t=5 hours \n" ); document.write( "Speed = s = \n" ); document.write( "Distance = d = 120 miles \n" ); document.write( "Speed of current = c \n" ); document.write( "Distance=(Speed of boat+ Speed of current) *time \n" ); document.write( "120=(s+c)*5 \n" ); document.write( "120/5=s+c \n" ); document.write( "24=s+c \n" ); document.write( "s+c=24………………………………………(2)\r \n" ); document.write( "\n" ); document.write( "Add (1) and (2) \n" ); document.write( "s-c=6……………………………………….(1) \n" ); document.write( "s+c=24………………………………………(2) \n" ); document.write( "-------------------- \n" ); document.write( "2s=30 \n" ); document.write( "s=30/2 \n" ); document.write( "s=15\r \n" ); document.write( "\n" ); document.write( "Speed of boat is 15miles/hour.\r \n" ); document.write( "\n" ); document.write( "Put the value of s in (1) \n" ); document.write( "s-c=6……………………………………….(1) \n" ); document.write( "15-c=6 \n" ); document.write( "-c=6-15 \n" ); document.write( "-c=-9 \n" ); document.write( "c=9\r \n" ); document.write( "\n" ); document.write( "Speed of current is 9miles/hour.\r \n" ); document.write( "\n" ); document.write( "Speed of boat without current = 15-9 = 6miles/hour \n" ); document.write( "Speed of boat with current = 15+9=24miles/hour\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Check \n" ); document.write( "====== \n" ); document.write( "120 miles in 20 hours upstream \n" ); document.write( "time*speed= distance \n" ); document.write( "time=distance/speed \n" ); document.write( "time=120/6=20hours\r \n" ); document.write( "\n" ); document.write( "120 miles in 5 hours downstream \n" ); document.write( "time*speed= distance \n" ); document.write( "time=distance/speed \n" ); document.write( "time=120/24=5hours \n" ); document.write( " \n" ); document.write( " |