Hi, to answer this question we have to write a system of equations:
n = number of nickel coins
q = number of quarter coins
Since there are 11 coins, the sum of the number of nickels and quarters must be 11:
n+q =11
Since:
1 nickel = $0.05
1 quarter = $0.25
The total value (1.15) must be equal to the product of the number of nickels (n) and the value of each nickel in dollars (0.05); plus the product of the number of quarters (q) and the value of each quarter in dollars (0.25)