Let q represent the number of quarters Abby has. Then the number of dimes she has is 49-q. The total amount of money she has in dimes and quarters is ...
25q +10(49 -q) = 835
15q + 490 = 835 . . . . . . simplify
q = (835 -490)/15 = 23 . . . . solve for q
Abby has 23 quarters and 26 dimes.
