document.write( "Question 126254: A person traveling 4 hour by plane and 25 hour by ship covers 1580 miles. If the speed of the plane had been one-half of the actual speed and speed of the ship had been one-fourth greater, the person would have traveled only 1315 miles in the same length of time. Find the speeds of the plane and the ship. \n" ); document.write( "
Algebra.Com's Answer #92619 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! A person traveling 4 hour by plane and 25 hour by ship covers 1580 miles. If the speed of the plane had been one-half of the actual speed and speed of the ship had been one-fourth greater, the person would have traveled only 1315 miles in the same length of time. Find the speeds of the plane and the ship. \n" ); document.write( ": \n" ); document.write( "Originally \n" ); document.write( "Let x = speed of the plane (mph) \n" ); document.write( "Let y = speed of the ship \n" ); document.write( "If: \n" ); document.write( ".5x = speed of the plane \n" ); document.write( "1.25y = speed of the ship \n" ); document.write( ": \n" ); document.write( "Write two distance equations: Distance = time * speed \n" ); document.write( ": \n" ); document.write( "Actual event equation: \n" ); document.write( "4x + 25y = 1580 \n" ); document.write( ": \n" ); document.write( "If event equation: \n" ); document.write( "4(.5x) + 25(1.25y) \n" ); document.write( "2x + 31.25y = 1315 \n" ); document.write( ": \n" ); document.write( "Use elimination here. Multiple above equation by 2, subtract \"Actual\" equation: \n" ); document.write( "4x + 62.5y = 2630 \n" ); document.write( "4x + 25y = 1580 \n" ); document.write( "-------------------Subtracting eliminates x \n" ); document.write( "0x + 37.5y = 1050 \n" ); document.write( "y = \n" ); document.write( "y = 28 mph is the ships original speed \n" ); document.write( ": \n" ); document.write( "Use equation; 4x + 25y = 1580; substitute 28 for y: \n" ); document.write( "4x + 25(28) = 1580 \n" ); document.write( "4x = 700 = 1580 \n" ); document.write( "4x = 1580 - 700 \n" ); document.write( "4x = 880 \n" ); document.write( "x = \n" ); document.write( "x = 220 mph plane's original speed \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "Check our solutions in the \"If event\" equation \n" ); document.write( "4(.5(220)) + 25(1.25(28)) = \n" ); document.write( "440 + 875 = 1315 \n" ); document.write( " |