Answer:
there are 9 quarters and 19 dimes
Step-by-step explanation:
Let x be the number of dimes and y the number of quarters
-dimes: 0.1x
-quarters: 0.25y
-the total amount of coins : x + y = 28
=> x = 28 - y
We have the equation:
0.25y + 0.1x = 4.15
0.25y + 0.1(28 - y) = 4.15
0.25y + 2.8 - 0.1y = 4.15
0.15y = 1.35
y = 9
x = 28 - y
= 28 - 9
= 19
