document.write( "Question 167692This question is from textbook Algebra structure and method
\n" ); document.write( ": sam has 30 nickles and dimes worth $2.40. How many nickles does he have? \n" ); document.write( "

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sam has 30 nickles and dimes worth $2.40. How many nickles does he have?
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\n" ); document.write( "Let n = nickles
\n" ); document.write( "and d = dimes
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\n" ); document.write( "We have two unknowns, so we'll need two equations:
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\n" ); document.write( "From: \"sam has 30 nickles and dimes\" we get equation 1:
\n" ); document.write( "n+d = 30
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\n" ); document.write( "From: \"worth $2.40\" we get equation 2:
\n" ); document.write( ".05n + .10d = 2.40
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\n" ); document.write( "Using \"elimination method\":
\n" ); document.write( "n+d = 30
\n" ); document.write( ".05n + .10d = 2.40
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\n" ); document.write( "multiply the top equation by -.05:
\n" ); document.write( "-.05n - .05d = -1.5
\n" ); document.write( " .05n + .10d = 2.40
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\n" ); document.write( "Add the two equations together:
\n" ); document.write( "-.05n - .05d = -1.5
\n" ); document.write( " .05n + .10d = 2.40
\n" ); document.write( "------------------------
\n" ); document.write( ".05d = .9
\n" ); document.write( "d = 18 (number of dimes)
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\n" ); document.write( "Substitute the above into equation 1 to find n:
\n" ); document.write( "n+d = 30
\n" ); document.write( "n+18 = 30
\n" ); document.write( "n = 30-18
\n" ); document.write( "n = 12 (number of nickles) \n" ); document.write( "

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