Question 1205719
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You can solve the problem informally, using steps that are nearly the same as the formal algebraic solution shown by the other tutor.<br>
Probably this problem was supposed to be solved using formal algebra; but you can get good mental exercise solving the problem without it.<br>
The value of the 5 "extra" dimes is 5($0.10) = $0.50; the value of the 6 "extra" quarters is 6($0.25) = $1.50.  The total value of those "extra" coins is $0.50  $1.50 = $2.00.<br>
So the value of the remaining coins is $6.80 - $2.00 = $4.80.<br>
Those coins are equal numbers of nickels, dimes, and quarters.  The total value of a group consisting of one nickel, one dime, and one quarter is $0.40.  To make the remaining $4.80, the number of those groups must be $4.80/$0.40 = 12.<br>
So the number of nickels is 12; the number of dimes is 12+5 = 17, and the number of quarters is 12+6 = 18.<br>
ANSWERS: 12 nickels, 17 dimes, 18 quarters<br>