document.write( "Question 107934: A person traveling 4 hr by plane and 25 hr by ship covers 1580 miles. If the speed of the plane had been one-half of the actual speed and the 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 #78733 by ankor@dixie-net.com(22740)\"\" \"About 
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A person traveling 4 hr by plane and 25 hr by ship covers 1580 miles. If the speed of the plane had been one-half of the actual speed and the 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.
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\n" ); document.write( "Let x = speed of the plane
\n" ); document.write( "Let y = speed of the ship
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\n" ); document.write( "Write two distance equations; Distance = time * speed
\n" ); document.write( ":
\n" ); document.write( "\"Actual\" equation:
\n" ); document.write( "4x + 25y = 1580
\n" ); document.write( ":
\n" ); document.write( "The \"If\" equation:
\n" ); document.write( ".5(4x) + 1.25(25y) = 1315
\n" ); document.write( "or
\n" ); document.write( "2x + 31.25y = 1315
\n" ); document.write( ":
\n" ); document.write( "Multiply the above equation by 2, subtract the \"actual\" equation
\n" ); document.write( "4x + 62.5y = 2630
\n" ); document.write( "4x + 25.0y = 1580
\n" ); document.write( "------------------- subtracting eliminates x
\n" ); document.write( "0x + 37.5y = 1050
\n" ); document.write( "y = 1050/37.5
\n" ); document.write( "y = 28 mph is the actual speed of the ship
\n" ); document.write( ":
\n" ); document.write( "Find x using the \"actual\" equation
\n" ); document.write( "4x + 25(28) = 1580
\n" ); document.write( "4x + 700 = 1580
\n" ); document.write( "4x = 1580 - 700
\n" ); document.write( "x = 880/4
\n" ); document.write( "x = 220 mph is the actual speed of the plane\r
\n" ); document.write( "\n" ); document.write( ":
\n" ); document.write( ":\r
\n" ); document.write( "\n" ); document.write( "Check solution using the \"IF\" equation
\n" ); document.write( ".5(4*220) + 1.25(25*28) =
\n" ); document.write( "440 + 875 = 1315
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