document.write( "Question 315423: Yoshi +12 years = her sister's age.
\n" ); document.write( "6 years from now the sum of their ages will equal 32.
\n" ); document.write( "What is Yoshi's present age? \n" ); document.write( "

Algebra.Com's Answer #226205 by moshiz08(60) $\"\"$ $\"About$

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We have the first equation $\"Y+%2B+12+=+S\"$ (where Y = yoshi's age, S = her sister's age) \r
\n" ); document.write( "\n" ); document.write( "For the second equation (6 years from now the sum of their ages will equal 32): six years from now we know that Yoshi's age will be Y+6. Her sister's age will be S+6. Thus the equation reads:
\n" ); document.write( " $\"%28Y%2B6%29+%2B+%28S%2B6%29+=+32\"$ . This is the same as combining like terms to give $\"Y+%2B+S+%2B+12+=+32\"$ or subtracting 12 from both sides to give $\"Y+%2B+S+=+20\"$ . \r
\n" ); document.write( "\n" ); document.write( "But we know from the first equation that $\"S+=+Y+%2B+12\"$ . Substitute this into $\"Y+%2B+S+=+20\"$ to give $\"Y+%2B+%28Y%2B12%29+=+20\"$ . Then combining like terms gives $\"2Y+%2B+12+=+20\"$ . Subtracting 12 from both sides gives $\"2Y+=+8\"$ . Dividing by 2 yields $\"Y+=+4\"$ . \r
\n" ); document.write( "\n" ); document.write( "Now we check. If yoshi is 4 years old, then his sister is 4+12 = 16 years old.
\n" ); document.write( "In six years, yoshi will be 10. His sister will be 22. The sum of their ages (10 + 22) gives us 32, so the answer yoshi is 4 works. \n" ); document.write( "

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