Answer:
There are 32 nickels and 23 dimes.
Explanation:
Lets say x is nickels and y is dimes
The first equation would be 55 = x + y
The second equation would be .05x + .10y = 3.90
The Solving Part:
Move y to the other side: x = 55 - y
Substitute x in the second equation: .05(55-y) + .10y = 3.90
Distribute, rearrange, and combine like terms: .05y = 1.15
Solve for y: Y = 23
Plug in 23 for y and solve: 55 - y = x ; 55 - 23 = x ; 55 - 23 = 32
x = 32
y = 23
32 nickels and 23 dimes