document.write( "Question 775854: X was twice as old as Y 10 years back. how old is Y if X will be 45 years old 15 years hence ? \n" ); document.write( "

Algebra.Com's Answer #473208 by psbhowmick(878) $\"\"$ $\"About$

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Let X be x years old and Y be y years old now.\r
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\n" ); document.write( "\n" ); document.write( "10 years back:
\n" ); document.write( "X was (x - 10) yrs old
\n" ); document.write( "Y was (y - 10) yrs old\r
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\n" ); document.write( "\n" ); document.write( "At that time X was twice as old as Y.
\n" ); document.write( "x - 10 = 2(y - 10)
\n" ); document.write( "x = 2y - 20 + 10
\n" ); document.write( "x = 2y - 10 ___________ (i)\r
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\n" ); document.write( "\n" ); document.write( "After 15 yrs from now, Y's age would be (y+15) yrs.
\n" ); document.write( "Given that after 15 yrs from now Y will be 45 yrs old.
\n" ); document.write( "y + 15 = 45
\n" ); document.write( "y = 45 - 15 = 30 ___________ (ii)\r
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\n" ); document.write( "\n" ); document.write( "Substituting the value of y from (ii) in (i)
\n" ); document.write( "x = 2*30 - 10 = 50\r
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\n" ); document.write( "\n" ); document.write( "So now X is 50 yrs old and Y is 30 yrs old. \n" ); document.write( "

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