Math
posted by George on .
The value of 25 coins, consisting of dimes and quarters, is $ 3.55. How many dimes are in the collection?

18 dimes = 1.80
7 qtrs = 1.75
Total = the $3.55
Can you work it backwards, as I have no idea how to set an equation. It was instinct for me to see that initially I had to break the 55cents down and then work with the $3.00.
I'm sorry I can't help with setting the equation. JJ 
Total number of coins = 25
Number of dimes = x
Number of quarters = 25  x
Value of 1 dime = .10
Value of 1 quarter = .25
Total value of coins = $3.55
The equation:
.10(x) + .25(25  x) = 3.55
.10x + 6.25  .25x = 3.55
.15x + 6.25 = 3.55
.15x = 2.7
x = 18 dimes
25  x = 25  18 = 7 quarters 
Ok thanks

34.67