Answer:
4 dimes, 3 quarters
Explanation:
Given that there are two variables with two different relationships, you can set up a system of equations and use the substitution method to first solve for one variable and then the other:
d + q = 7
0.10d + 0.25q = 1.15
Solve for 'q' in the first equation: q = 7 - d
Substitute the express '7 - d' for 'q' in the second equation:
0.10d + 0.25(7 - d) = 1.15
Distribute: 0.10d + 1.75 - 0.25d = 1.15
Combine like terms: 1.75 - 0.15d = 1.15
Subtract 1.75 from both sides: -0.15d = -0.6
Divide both sides by -0.15: d = 4
Solve for q: 3 + q = 7 or q = 4