document.write( "Question 368931: Mandy has 11 coins in dimes and quarters. The value of her coins is $2.15. How many dimes does she have? \n" ); document.write( "

Algebra.Com's Answer #262922 by lkellhomes(6) $\"\"$ $\"About$

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Given that the number of dimes and the number of quarters totals 11, we can set up two equations.
\n" ); document.write( "d + q = 11
\n" ); document.write( "The value of a dime is .10 and the value of a quarter is .25
\n" ); document.write( "so the value of each coin is multiplied by the quantity of each coin.
\n" ); document.write( ".10d + .25q = $2.15
\n" ); document.write( "We now have two equations and two unknowns. Use substitution to solve
\n" ); document.write( "Equation 1: d + q = 11 or q = 11 - d
\n" ); document.write( "Equation 2: .10d + .25q = $2.15\r
\n" ); document.write( "\n" ); document.write( "Substitute the modified Equation 1 into Equation 2\r
\n" ); document.write( "\n" ); document.write( ".10d + .25q = 2.15
\n" ); document.write( ".10d + .25(11-d) = 2.15 ----distribute
\n" ); document.write( ".10d + 2.75 - .25d = 2.15 ---combine like terms
\n" ); document.write( "-.15d + 2.75 = 2.15 ----subtract 2.75 from both sides
\n" ); document.write( "-.15d = -.60 ----divide both sides by .15
\n" ); document.write( "d = 4
\n" ); document.write( "Mandy has 4 dimes \n" ); document.write( "

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