OEQuote:
Explanation: let n = # of nickels, d = # of dimes, and q = # of quarters.
Then, n = 3d and q = d+6. Each nickel is worth 0.05 dollars, each dime
0.10, and each quarter 0.25, and it all has to add up to $22.50. So (0.05)n
+ (0.10)d + (0.25)q = 22.50. Multiply through by 100 to clear the
decimals, to get 5n + 10d + 25q = 2250. Now, put everything in terms of
d: 5(3d) + 10d + 25(d+6) = 2250. Multiply through: 15d + 10d + 25d
+150 = 2250. Combine like terms and solve for d: 50d =2100, so d = 42.
Then n = 3d = 126 and q = 48. The value of 48 quarters is 48(0.25) =
$12.00.