Question 1177788
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The response from the other tutor shows one formal algebraic solution.<br>
If formal algebra is not required, and the speed of obtaining an answer is important (as in a timed math competition), here is an easy informal way to find the answer to this or any number of similar problems.<br>
(1) Suppose all 60 coins were dimes; the total value would be $6.00; the actual total is $6.30 more than that.
(2) Imagine switching a dime for a quarter; that keeps the total number of coins the same but increases the total value by 15 cents.
(3) The number of times you need to switch a dime for a quarter to make the additional $6.30 = 630 cents is 630/15 = 42.<br>
So you end up with...<br>
ANSWER: 42 quarters and 60-42=18 dimes<br>
CHECK: 42(25)+18(10) = 1050+180 = 1230<br>