Tony has saved dimes and quarters in his piggy bank he has saved a total of four dollars and has 25 coins how many dimes does he have and how many quarters does he have

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.