document.write( "Question 1147373: Suppoise i have a coin collection of dimes and quarters containing 46 coins. If i have $6/70, how many of each type of coin do i have? \n" ); document.write( "

Algebra.Com's Answer #768689 by greenestamps(13200) $\"\"$ $\"About$

You can put this solution on YOUR website!

\n" ); document.write( "Algebraically....

\n" ); document.write( "d+q = 46
\n" ); document.write( "10d+25q = 670

\n" ); document.write( "Multiply the first equation by 10 and subtract the resulting equation from the second:

\r\n" );
document.write( "  10d + 25q = 670\r\n" );
document.write( "  10d + 10q = 460\r\n" );
document.write( " -----------------\r\n" );
document.write( "        15q = 210

\n" ); document.write( "Divide by 15 to find the number of quarters, q; then substitute in either of the original equations to find d.

\n" ); document.write( "You can do exactly the same calculations to solve the problem informally, without algebra:

\n" ); document.write( "(1) If all 46 coins were dimes, the value would be $4.60.
\n" ); document.write( "(2) The actual value is $6.70, which is $2.10, or 210 cents, more than $4.60.
\n" ); document.write( "(3) The difference between the value of a quarter and a dime is 15 cents.
\n" ); document.write( "(4) Divide 210 by 15 to find the number of quarters.
\n" ); document.write( "(5) Subtract the number of quarters from the total number of coins to find the number of dimes. \n" ); document.write( "

\n" );