document.write( "Question 285547: A purse contains a collection of quarters, dimes, nickels, and pennies. The average value of the coins in the purse is 17 cents. If a penny is removed from the purse, the average value of the coins becomes 18 cents. How many nickels are in the purse?\r
\n" ); document.write( "\n" ); document.write( "(A) 2 (B) 5 (C) 0 (D) 1 (E) 8
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Algebra.Com's Answer #207001 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
The average value would be
\n" ); document.write( "(total value)/(number of coins)
\n" ); document.write( "Let \"q\" = number of quarters
\n" ); document.write( "Let \"d\" = number of dimes
\n" ); document.write( "Let \"n\" = number of nickels
\n" ); document.write( "Let \"p\" = number of pennies
\n" ); document.write( "given:
\n" ); document.write( "(1) \"%2825q+%2B+10d+%2B+5n+%2B+p%29%2F%28q+%2B+d+%2B+n+%2B+p%29+=+17\" (in cents)
\n" ); document.write( "(1) \"25q+%2B+10d+%2B+5n+%2B+p+=+17%2A%28q+%2B+d+%2B+n+%2B+p%29\"
\n" ); document.write( "and
\n" ); document.write( "\"%2825q+%2B+10d+%2B+5n+%2B+1%2A%28p+-+1%29%29%2F%28q+%2B+d+%2B+n+%2B+p+-+1%29+=+18\"
\n" ); document.write( "\"25q+%2B+10d+%2B+5n+%2B+p+-+1+=+18%2A%28q+%2B+d+%2B+n+%2B+p+-+1%29\"
\n" ); document.write( "(2) \"25q+%2B+10d+%2B+5n+%2B+p+=+18%2A%28q+%2B+d+%2B+n+%2B+p+-+1%29+%2B+1\"
\n" ); document.write( "Comparing (1) and (2) I can say
\n" ); document.write( "\"17%2A%28q+%2B+d+%2B+n+%2B+p%29+=+18%2A%28q+%2B+d+%2B+n+%2B+p+-+1%29+%2B+1\"
\n" ); document.write( "\"17%2A%28q+%2B+d+%2B+n+%2B+p%29+=+18%2A%28q+%2B+d+%2B+n+%2B+p%29+-+17\"
\n" ); document.write( "Subtract \"17%2A%28q+%2B+d+%2B+n+%2B+p%29\" from both sides
\n" ); document.write( "\"0+=+q+%2B+d+%2B+n+%2B+p+-+17\"
\n" ); document.write( "\"q+%2B+d+%2B+n+%2B+p+=+17\"
\n" ); document.write( "Going back to (1),
\n" ); document.write( "(1) \"%2825q+%2B+10d+%2B+5n+%2B+p%29%2F%28q+%2B+d+%2B+n+%2B+p%29+=+17\"
\n" ); document.write( "(1) \"%2825q+%2B+10d+%2B+5n+%2B+p%29%2F17+=+17\"
\n" ); document.write( "\"25q+%2B+10d+%2B+5n+%2B+p+=+289\" (in cents)
\n" ); document.write( "There must be \"17\" coins, making \"289\" cents
\n" ); document.write( "I know there must be at least \"4\" pennies
\n" ); document.write( "and there could be \"9\" or \"14\" pennies
\n" ); document.write( "There can't be \"12\" quarters, since that adds to \"300\" cents
\n" ); document.write( "There can't be \"11\" quarters either, since \"1\" dime and
\n" ); document.write( "\"1\" nickel make \"275+%2B+10+%2B+5+=+290\" -too much
\n" ); document.write( "Suppose there are \"10\" quarters, \"1\" dime, \"1\" nickel,
\n" ); document.write( "and \"4\" pennies
\n" ); document.write( "That makes \"250+%2B+10+%2B+5+%2B+4+=+269\", but \"10+%2B+1+%2B+1+%2B+4+=+16\" coins
\n" ); document.write( "and I can't make up \"20\" cents with \"1\" more coin
\n" ); document.write( "I'm guessing there are \"9\" quarters -you can figure out the rest\r
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