SOLUTION: You took $10 in quarters, dimes and nickels from a jar of spare change. If you have twice as many quarters as nickels and 10 more dimes than quarters, how many coins of each type d

Let number of nickels be N

Then number of quarters  = 2N, and number of dimes  = 2N + 10

We then get: .05N + .25(2N) + .1(2N + 10) = 10

.05N + .5N + .2N + 1 = 10

.75N = 9

N, or number of nickels =  

You should be able to find the number of quarters and dimes! 

Put aside 10 dimes for a moment.

Then the remaining  9 dollars coin collection you can separate into groups containing 2 quarters, 1 nickel and 2 dimes each.


Each such a group is worth  2*25 + 5 + 2*10 = 75 cents.


The number of such groups is  900 cents divided by 75 cents, i.e. 12.


So the original collection has 12 nickels, 24 quarters and 24+10 = 34 dimes.