document.write( "Question 1116901: A teacher is four times as old as a student. In 12 years, the student’s age will be half of the teacher’s age. How old are they now? \n" ); document.write( "

Algebra.Com's Answer #731809 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+a+\"$ = the teacher's age now
\n" ); document.write( "Let $\"+b+\"$ = the student's age now
\n" ); document.write( "-----------------------------------
\n" ); document.write( "(1) $\"+a+=+4b+\"$
\n" ); document.write( "(2) $\"+b+%2B+12+=+%281%2F2%29%2A%28+a+%2B+12+%29+\"$
\n" ); document.write( "-----------------------------------
\n" ); document.write( "(2) $\"+2b+%2B+24+=+a+%2B+12+\"$
\n" ); document.write( "Plug (1) into (2)
\n" ); document.write( "(2) $\"+2b+%2B+24+=+4b+%2B+12+\"$
\n" ); document.write( "(2) $\"+2b+=+12+\"$
\n" ); document.write( "(2) $\"+b+=+6+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+a+=+4b+\"$
\n" ); document.write( "(1) $\"+a+=+4%2A6+\"$
\n" ); document.write( "(1) $\"+a+=+24+\"$
\n" ); document.write( "The teacher is 24
\n" ); document.write( "The student is 6
\n" ); document.write( "---------------------
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+b+%2B+12+=+%281%2F2%29%2A%28+a+%2B+12+%29+\"$
\n" ); document.write( "(2) $\"+6+%2B+12+=+%281%2F2%29%2A%28+24+%2B+12+%29+\"$
\n" ); document.write( "(2) $\"+18+=+%281%2F2%29%2A36+\"$
\n" ); document.write( "(2) $\"+18+=+18+\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

\n" );