SOLUTION: a child has $17.55 worth of nickels and dimes in her piggy bank. There are a total of 207 coins. How many of each does she have?

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Question 660238: a child has $17.55 worth of nickels and dimes in her piggy bank. There are a total of 207 coins. How many of each does she have?
Answer by ReadingBoosters(3246) About Me  (Show Source):
You can put this solution on YOUR website!
x = # of nickels
y = # of dimes
x + y = 207
.05x + .1y = 17.55
Multiply the first equation by -.05 and add the second equation
-.05(x+y=207)
-.05x - .05y = -10.35
-.05x + .05x - .05y + .1y = -10.35 + 17.55
Combine like terms
.05y = 7.2
.05y/.05 = 7.2/.05
y = 144 dimes
Plug into first equation
x + 144 = 207
x = 207 - 144
x = 63 nickles
Proof
(.1)144 = 14.40
(.05)63 = 3.15
14.40+3.15=17.55