Treavor, how much is each coin worth? We also have how many of each we have compared to quarters, so let's let q = the number of quarters.
So, the number of dimes is 2q, right? Since we have five more nickels than dimes, we have 2q + 5.
Now, we know how much each coin is worth, so .25q + .10(2q) + .05(2q + 5) = 3.00.
Can you solve from here? What I would start with is multiplying both sides by 100 to get:
25q + 10(2q) + 5(2q + 5) = 300.