document.write( "Question 89511: I just need help setting up the equation. It's from Algebra, Part 3 from Thomson Education Direct. It's a career oriented study unit. # of book is 2469C-1\r
\n" );
document.write( "\n" );
document.write( "A person travels 4 hrs by plane and 25 hrs by ship and covers a total distance of 1580 miles. If the plane's speed would have been 1/2 of the actual speed and the ship's speed 1/4 greater than the actual speed, a distance of 1315 miles would have been travelled. Find the speeds of the plane and the ship. \n" );
document.write( "
Algebra.Com's Answer #65065 by ankor@dixie-net.com(22740) You can put this solution on YOUR website! A person travels 4 hrs by plane and 25 hrs by ship and covers a total distance of 1580 miles. If the plane's speed would have been 1/2 of the actual speed and the ship's speed 1/4 greater than the actual speed, a distance of 1315 miles would have been traveled. Find the speeds of the plane and the ship. \n" ); document.write( ": \n" ); document.write( "Let x = actual speed of the plane; and: y = actual speed of the ship \n" ); document.write( ": \n" ); document.write( "Write 2 distance equations; Dist = time * speed: \n" ); document.write( ": \n" ); document.write( "4x + 25y = 1580; actual speed equation \n" ); document.write( ": \n" ); document.write( "We also have: \n" ); document.write( "\"If the plane's speed would have been 1/2 of the actual speed and the ship's speed 1/4 greater than the actual speed, a distance of 1315 miles \" \n" ); document.write( ": \n" ); document.write( "Equation for this would be: \n" ); document.write( " \n" ); document.write( ": \n" ); document.write( "Mult equation by 4 to get rid of these fractions and we have: \n" ); document.write( "2(4x) + 5(25y) = 5260 \n" ); document.write( ": \n" ); document.write( "8x + 125y = 5260; the \"if...\" equation \n" ); document.write( ": \n" ); document.write( "Multiply the actual equation by 2 and subtract it from the above equation \n" ); document.write( "8x + 125y = 5260 \n" ); document.write( "8x + 50y = 3160 \n" ); document.write( "---------------- subtraction eliminates x \n" ); document.write( "0x + 75y = 2100 \n" ); document.write( "y = 2100/75 \n" ); document.write( "y = 28 mph is the ships speed \n" ); document.write( ": \n" ); document.write( "Use the actual speed equation to find x \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 = 880/4 \n" ); document.write( "x = 220 mph is the speed of the plane \n" ); document.write( ": \n" ); document.write( "Check solutions in the \"if..\" equation \n" ); document.write( " \n" ); document.write( ": \n" ); document.write( "440 + 875 = 1315 \n" ); document.write( "; \n" ); document.write( ": \n" ); document.write( "Did this help you?\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |