document.write( "Question 149206: Joe has a collection of nickels and dimes tha is worth$5.65. If the number of dimes were doubled and the number of nickels were increased by 8, the value of the coins would be $10.45. How may dimes does he have? Please show all work...\r
\n" ); document.write( "\n" ); document.write( "So far all I can come up with is x =dimes, y= nickels.
\n" ); document.write( "x(2), y+8 =$10.45
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Algebra.Com's Answer #109460 by nerdybill(7384)\"\" \"About 
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\n" ); document.write( "Here's your solution:
\n" ); document.write( "Let n = number of nickels
\n" ); document.write( "and d = number of dimes
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\n" ); document.write( "Because we have two unknowns we need two equations:
\n" ); document.write( "From: \"Joe has a collection of nickels and dimes that is worth $5.65.\" we get
\n" ); document.write( ".05n + .10d = 5.65 (equation 1)
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\n" ); document.write( "From: \"If the number of dimes were doubled and the number of nickels were increased by 8, the value of the coins would be $10.45.\" we get:
\n" ); document.write( ".05(n+8) + .10(2d) = 10.45
\n" ); document.write( ".05n + .40 + .20d = 10.45
\n" ); document.write( ".05n + .20d = 10.05 (equation 2)
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\n" ); document.write( "n = 25 (nickels)
\n" ); document.write( "d = 44 (dimes)
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\n" ); document.write( "Below shows the details:
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Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
\n" ); document.write( " We'll use substitution. After moving 0.1*d to the right, we get:
\n" ); document.write( " \"0.05%2An+=+5.65+-+0.1%2Ad\", or \"n+=+5.65%2F0.05+-+0.1%2Ad%2F0.05\". Substitute that
\n" ); document.write( " into another equation:
\n" ); document.write( " \"0.05%2A%285.65%2F0.05+-+0.1%2Ad%2F0.05%29+%2B+0.2%5Cd+=+10.05\" and simplify: So, we know that d=44. Since \"n+=+5.65%2F0.05+-+0.1%2Ad%2F0.05\", n=25.
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\n" ); document.write( " Answer: \"system%28+n=25%2C+d=44+%29\".
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