Answer:
Step-by-step explanation:
Let q represent the number of quarters. Then Tony's coin value is ...
0.25q +0.10(25 -q) = 4.00
0.15q +2.50 = 4.00 . . . . . . . . eliminate parentheses, collect terms
0.15q = 1.50 . . . . . . . . . . . . . . subtract 2.50
q = 10 . . . . . . . . . . . . . . . . . . . . divide by the coefficient of q
Then the number of dimes is ...
25 -10 = 15
Tony has 15 dimes and 10 quarters.