Question 1132844
The total value of quarters and dimes in a coin bank is $6.90.
If the quarters were dimes and the dimes were quarters the total value of the coins would be $7.80.
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25q + 10d = 690
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Each swap of a dime for a quarter adds 15 cents.
780 - 690 = 90
90/15 = 6 swaps, which is the difference between the # of d's and q's
Since the total increases, d > q
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d - q = 6
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10d + 25q = 690 --> 5q + 2d = 138
2d + 5q = 138
2d - 2q = 12
-------------------- Subtract
7q = 126
q = 18 quarters
d = 24 dimes