Question 1096549
<br>Despite the sloppy wording of your question, the intention is clear....<br>
For an informal solution, first imagine that all 35 coins are dimes; the amount would then be $3.50.  But the actual amount is $2.20, which is $1.30 less than $3.50.<br>
Next imagine replacing 1 dime with 1 nickel repeatedly.  Each time you do that, the total value goes down by $0.05 (5 cents).  How many times do you need to do that to get the total down to the actual amount of $2.20?<br>
The value goes down by $0.05 each time; you need to reduce the value by $1.30.  $1.30 divided by $0.05 is 26; you need to replace 26 of the dimes with nickels.<br>
So there are 26 nickels, which means the number of dimes is 35-26 = 9.<br>
CHECK: 9($0.10) + 26($0.05) = $0.90 + $1.30 = $2.20.