document.write( "Question 258041: A person traveling 4hr 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 ship? \n" ); document.write( "
Algebra.Com's Answer #189888 by drk(1908)\"\" \"About 
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This is an RTD problem. Let RS = rate of ship, and Rp = rate of plane. Here is a table based on the given information:
\n" ); document.write( "transport . . . . . . . .rate . . . . . . . .time . . . . . . .distance
\n" ); document.write( "PLANE . . . . . . . . . .Rp . . . . . . . . .4 . . . . . . . . .4Rp
\n" ); document.write( "SHIP . . . . . . . . . .Rs . . . . . . . . . .25 . . . . . . . . 25Rs
\n" ); document.write( "TOTAL . . . . . . . . . . . . . . . . . . . .29 . . . . . . . . .1580
\n" ); document.write( "So, we get from column 3,
\n" ); document.write( "(i) \"4Rp+%2B+25Rs+=+1580\"
\n" ); document.write( "We are now given additional information and it looks like this:
\n" ); document.write( "(ii) \"%281%2F2%29Rp%2A4+%2B+%285%2F4%29Rs%2A25+=+1315\"
\n" ); document.write( "multiply (ii) by 2 and we get
\n" ); document.write( "(iii) \"4Rp+%2B+62.5Rs+=+2630\"
\n" ); document.write( "Solve (i) for 4Rp and we get
\n" ); document.write( "(iv) \"4Rp+=+1580+-+25Rs\"
\n" ); document.write( "substituting (iv) into (iii), we get
\n" ); document.write( "(v) \"1580+-+25Rs+%2B+62.5Rs+=+2630\"
\n" ); document.write( "solving for Rs, we get
\n" ); document.write( "(vi) \"1580+%2B37.5Rs+=+2630\"
\n" ); document.write( "and then
\n" ); document.write( "(vii) \"37.5Rs+=+1050\"
\n" ); document.write( "So,
\n" ); document.write( "Rs = 28
\n" ); document.write( "and
\n" ); document.write( "Rp = 220.\r
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