document.write( "Question 681003: How do you solve \"mark has twice as many quarters as nickels and three more dimes than nickels. he has $4.20 in all. how many of each does he have? in system of equations form
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Algebra.Com's Answer #422545 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+q+\"$ = number of quarters he has
\n" ); document.write( "Let $\"+d+\"$ = number of dimes he has
\n" ); document.write( "Let $\"+n+\"$ = number of nickels he has
\n" ); document.write( "---------------------------------
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"+q+=+2n+\"$
\n" ); document.write( "(2) $\"+d+=+n+%2B+3\"$
\n" ); document.write( "(3) $\"+25q+%2B+10d+%2B+5n+=+420+\"$ ( in cents )
\n" ); document.write( "---------------------------
\n" ); document.write( "Substitute (1) and (2) into (3)
\n" ); document.write( "(3) $\"+25%2A%282n%29+%2B+10%2A%28n+%2B+3%29+%2B+5n+=+420+\"$
\n" ); document.write( "(3) $\"+50n+%2B+30+%2B+10n+%2B+5n+=+420+\"$
\n" ); document.write( "(3) $\"+65n+=+390\"$
\n" ); document.write( "(3) $\"+n+=+6+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+q+=+2n+\"$
\n" ); document.write( "(1) $\"+q+=+2%2A6+\"$
\n" ); document.write( "(1) $\"+q+=+12+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+d+=+n+%2B+3\"$
\n" ); document.write( "(2) $\"+d+=+6+%2B+3\"$
\n" ); document.write( "(2) $\"+d+=+9+\"$
\n" ); document.write( "Mark has 12 quarters, 9 dimes, and 6 nickels
\n" ); document.write( "check:
\n" ); document.write( "(3) $\"+25q+%2B+10d+%2B+5n+=+420+\"$
\n" ); document.write( "(3) $\"+25%2A12+%2B+10%2A9+%2B+5%2A6+=+420+\"$
\n" ); document.write( "(3) $\"+300+%2B+90+%2B+30+=+420+\"$
\n" ); document.write( "(3) $\"+420+=+420+\"$
\n" ); document.write( "OK\r
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