Question 169935
you have one hundred coins in your coin jar, consisting of nickels, dimes and quarters. the total value of the coins is &11.80 and you have 10 more nickels than dimes. How many of each coin do you have? 
x=dimes 
x +10= nickels 
90-2x= quarters 
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What you have is correct. 
Then add:
10*x + 5*(x+10) + 25*(90-2x) = 1180
You can do it from here, I'm sure, but...
10x + 5x+50 + 2250-50x = 1180
-35x = -1120
x = 32 dimes (= $3.20)
42 = nickels (= $2.10)
26 = quarters (= $6.50)
100 coins------$11.80