Question 1103569
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If you are looking for a fast way to find the answer, without a need to use formal algebra, then you can use logical reasoning like this....<br>
If all 18 coins were dimes, the total value would be $1.80.
The actual value, $3.30, is $1.50 more than $1.80.
Each quarter is worth $0.15 more than each dime.
So the number of quarters is {{{1.50/0.15 = 10}}}.<br>
And 10 quarters means 8 dimes.