document.write( "Question 1152784: Roger has 27 standard U.S. coins worth a total of $3.65. No coin is worth more than 30¢ or less
\n" ); document.write( "than 3¢. How many dimes could Roger have? (NOTE: There are several possible answers, but
\n" ); document.write( "you only need to give TWO correct answers.)
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Algebra.Com's Answer #774877 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "List out the various coins
\n" ); document.write( "{penny, nickel, dime, quarter, half dollar, silver dollar}
\n" ); document.write( "We are told that no coin is less than 3 cents, so we can cross off the penny
\n" ); document.write( "{penny, nickel, dime, quarter, half dollar, silver dollar}
\n" ); document.write( "leaving us with this set
\n" ); document.write( "{nickel, dime, quarter, half dollar, silver dollar}\r
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\n" ); document.write( "\n" ); document.write( "and we are also told that no coin is worth more than 30 cents, so we can cross off the half dollar and silver dollar coins
\n" ); document.write( "{nickel, dime, quarter, half dollar, silver dollar}
\n" ); document.write( "leaving us with
\n" ); document.write( "{nickel, dime, quarter}\r
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\n" ); document.write( "\n" ); document.write( "Therefore, the coins we're dealing with are: {nickel, dime, quarter}\r
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\n" ); document.write( "\n" ); document.write( "n = number of nickels
\n" ); document.write( "d = number of dimes
\n" ); document.write( "q = number of quarters\r
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\n" ); document.write( "\n" ); document.write( "n+d+q = 27 because we have 27 coins
\n" ); document.write( "Solve for q to get q = 27-n-d\r
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\n" ); document.write( "\n" ); document.write( "5n = value, in cents, of all the nickels
\n" ); document.write( "10d = value, in cents, of all the dimes
\n" ); document.write( "25q = value, in cents, of all the quarters
\n" ); document.write( "5n+10d+25q = total value of all the coins
\n" ); document.write( "total value = 365 cents = 3.65 dollars
\n" ); document.write( "5n+10d+25q = 365\r
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\n" ); document.write( "\n" ); document.write( "5n+10d+25q = 365
\n" ); document.write( "5n+10d+25(27-n-d) = 365 ... plug in q = 27-n-d
\n" ); document.write( "5n+10d+25(27)+25(-n)+25(-d) = 365 ... distribute
\n" ); document.write( "5n+10d+675-25n-25d = 365
\n" ); document.write( "-20n-15d+675 = 365
\n" ); document.write( "-20n-15d+675-675 = 365-675 ... subtract 675 from both sides
\n" ); document.write( "-20n-15d = -310
\n" ); document.write( "-5(4n+3d) = -310
\n" ); document.write( "4n+3d = 62 .... divide both sides by -5\r
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\n" ); document.write( "\n" ); document.write( "Now solve for n
\n" ); document.write( "4n+3d = 62
\n" ); document.write( "4n = -3d+62
\n" ); document.write( "n = (-3d+62)/4
\n" ); document.write( "n = (-3d+2+60)/4
\n" ); document.write( "n = (-3d+2)/4+60/4
\n" ); document.write( "n = (-3d+2)/4+15
\n" ); document.write( "Through trial and error, you'll find that d = 2 makes the expression (-3d+2)/4 result in an integer
\n" ); document.write( "n = (-3d+2)/4+15
\n" ); document.write( "n = (-3*2+2)/4+15
\n" ); document.write( "n = (-6+2)/4+15
\n" ); document.write( "n = -4/4+15
\n" ); document.write( "n = -1+15
\n" ); document.write( "n = 14
\n" ); document.write( "So we have d = 2 dimes pair up with n = 14 nickels.\r
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\n" ); document.write( "\n" ); document.write( "If d = 2 and n = 14, then,
\n" ); document.write( "q = 27-n-d
\n" ); document.write( "q = 27-2-14
\n" ); document.write( "q = 11\r
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\n" ); document.write( "\n" ); document.write( "--------\r
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\n" ); document.write( "\n" ); document.write( "Now increase d = 2 to d = 6. This is an increase of +4, which is from the denominator of 4 in (-3d+2)/4\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "We have,
\n" ); document.write( "n = (-3d+2)/4+15
\n" ); document.write( "n = (-3*6+2)/4+15
\n" ); document.write( "n = (-18+2)/4+15
\n" ); document.write( "n = -16/4+15
\n" ); document.write( "n = -4+15
\n" ); document.write( "n = 11\r
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\n" ); document.write( "\n" ); document.write( "Now use n = 11 and d = 6 to get,
\n" ); document.write( "q = 27-n-d
\n" ); document.write( "q = 27-11-6
\n" ); document.write( "q = 10\r
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\n" ); document.write( "\n" ); document.write( "Two solutions are
\n" ); document.write( "(n,d,q) = (14,2,11)
\n" ); document.write( "and
\n" ); document.write( "(n,d,q) = (11,6,10)\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "For the solution (n,d,q) = (14,2,11), we can say
\n" ); document.write( "5n = 5*14 = 70 cents is from the nickels only
\n" ); document.write( "10d = 10*2 = 20 cents is from the dimes only
\n" ); document.write( "25q = 25*11 = 275 cents is from the quarters only
\n" ); document.write( "5n+10d+25q = 70+20+275 = 365 cents = $3.65 is the total combined value
\n" ); document.write( "This confirms the solution (n,d,q) = (14,2,11)\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "For the solution (n,d,q) = (11,6,10), we can say
\n" ); document.write( "5n = 5*11 = 55 cents is from the nickels only
\n" ); document.write( "10d = 10*6 = 60 cents is from the dimes only
\n" ); document.write( "25q = 25*10 = 250 cents is from the quarters only
\n" ); document.write( "5n+10d+25q = 55+60+250 = 365 cents = $3.65 is the total combined value
\n" ); document.write( "This confirms the solution (n,d,q) = (11,6,10)\r
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\n" ); document.write( "\n" ); document.write( "There are 5 total ways to have nickels, dimes, and quarters combine to $3.65 such that we have 27 coins total
\n" ); document.write( "\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "\n" ); document.write( "
CaseNickelsDimesQuarters
A2187
B5148
C8109
D11610
E14211

\n" ); document.write( "Each row adds to 27.
\n" ); document.write( "The solutions we found earlier are in cases D and E of this table.\r
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\n" ); document.write( "\n" ); document.write( "So Roger could have 6 dimes (case D) or he could have 2 dimes (case E).
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