Question 1006406
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Ron has 15 coins with a value of $2.55. The coins are nickels and quarters. How many of each coin does he have?
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q + n = 15
25q + 5n = 255
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I also can solve it using the mental math only:


q = {{{(255-15*5)/(25-5)}}} = {{{(255-75)/20}}} = {{{180/20}}} = 9 quarters. 


n = 15 - 9 = 6 nickels.


See the lesson &nbsp;<A HREF=http://www.algebra.com/algebra/homework/word/coins/Solving-coin-problem-without-equations.lesson>Solving coin problems without using equations</A>&nbsp; in this site.