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in a two digit number,if one is added to the ten's digit,it is four times the unit's digit.
\n" ); document.write( "if 18 times the unit's digit is subtracted from the number then the number
\n" ); document.write( " becomes half it's original value.
\n" ); document.write( "find the two digit number
\n" ); document.write( ":
\n" ); document.write( "Let x = the 10's digit
\n" ); document.write( "Let y = the units
\n" ); document.write( "then
\n" ); document.write( "10x+y = the number
\n" ); document.write( ":
\n" ); document.write( "Write an equation for each statement:
\n" ); document.write( ":
\n" ); document.write( "\"if one is added to the ten's digit, it is four times the unit's digit.\"
\n" ); document.write( "x + 1 = 4y
\n" ); document.write( "x = 4y - 1
\n" ); document.write( ":
\n" ); document.write( "\"if 18 times the unit's digit is subtracted from the number then the number
\n" ); document.write( " becomes half it's original value.\"
\n" ); document.write( "10x+y - 18y = .5(10x+y)
\n" ); document.write( "10x - 17y = 5x + .5y
\n" ); document.write( "10x - 5x = .5y + 17y
\n" ); document.write( "5x = 17.5y
\n" ); document.write( "Replace x with (4y-1)
\n" ); document.write( "5(4y-1) = 17.5y
\n" ); document.write( "20y - 5 = 17.5y
\n" ); document.write( "20y - 17.5y = 5
\n" ); document.write( "2.5y = 5
\n" ); document.write( "y = 5/2.5
\n" ); document.write( "y = 2
\n" ); document.write( "find x
\n" ); document.write( "x = 4y - 1
\n" ); document.write( "x = 7
\n" ); document.write( ":
\n" ); document.write( "72 is the number
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check solution in the statement:
\n" ); document.write( "if 18 times the unit's digit is subtracted from the number then the number becomes half it's original value.\"
\n" ); document.write( "72 - 18(2) = .5(72)
\n" ); document.write( "72 - 36 = 36, confirms our solution \n" ); document.write( "