Question 1193413
<br>
If your mental arithmetic is good, you can solve the problem informally using exactly the same calculations used in the formal algebraic solution shown by the other tutor.<br>
(1) The total value is $15.80
(2) Take away the "extra" 19 quarters. $15.80 - 19($0.25) = $15.80 - $4.75 = $11.05
(3) Group the remaining coins in groups of 3 quarters and 1 dime, each with a total value of 3($0.25)+1($0.10)=$0.85
(4) The number of those groups needed to make the remaining $11.05 is $11.05/$0.85 = 13<br>
So in those 13 groups there are a total of 39 quarters and 13 dimes; now add back in the other 19 quarters to get the final answer of 39+19=58 quarters and 13 dimes.<br>