document.write( "Question 618972: the tens of a two digit number is twice the units digit. if the number is multiplied by the sum of its digits the product is 63. whats the number? \n" ); document.write( "

Algebra.Com's Answer #389213 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+t+\"$ = the tens digit
\n" ); document.write( "Let $\"+u+\"$ = the units digit
\n" ); document.write( "The actual number is $\"+10t+%2B+u+\"$
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"+t+=+2u+\"$
\n" ); document.write( "(2) $\"+%28+t+%2B+u+%29%2A%28+10t+%2B+u+%29+=+63+\"$
\n" ); document.write( "-------------------------
\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) $\"+%28+2u+%2B+u+%29%2A%28+10%2A2u+%2B+u+%29+=+63+\"$
\n" ); document.write( "(2) $\"+3u+%2A+21u+=+63+\"$
\n" ); document.write( "(2) $\"+21u+=+21+\"$
\n" ); document.write( "(2) $\"+u+=+1+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+t+=+2u+\"$
\n" ); document.write( "(1) $\"+t+=+2+\"$
\n" ); document.write( "The number is 21
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+%28+t+%2B+u+%29%2A%28+10t+%2B+u+%29+=+63+\"$
\n" ); document.write( "(2) $\"+%28+2+%2B+1+%29%2A%28+10%2A2+%2B+1+%29+=+63+\"$
\n" ); document.write( "(2) $\"+3%2A21+=+63+\"$
\n" ); document.write( "(2) $\"+63+=+63+\"$
\n" ); document.write( "OK \n" ); document.write( "

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