Question 1051522:  Isaiah has 7.15 in dimes and nickels. He has a total of 91 coins 
 
 Answer by Boreal(15235)      (Show Source): 
You can  put this solution on YOUR website! x=dimes 
y=nickels 
x+y=91; that is a count of the coins. 
.10x+.05y=7.15; this is a count of the money 
multiply the bottom by -20, to make the second term -1 y, because then we can eliminate y 
-2x-y=-143.0 
-x=-52 
y=52 dimes or $5.20 
x=39 nickels or $1.95 
They sum to $7.15. 
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