Step 1 :Let's denote the number of dimes as x and the number of nickels as y. We know that a dime is worth 10 cents and a nickel is worth 5 cents.
Step 2 :We can set up the following two equations based on the information given: \(x + y = 91\) (total number of coins) and \(10x + 5y = 680\) (total value of coins in cents).
Step 3 :Solving this system of equations will give us the values of x and y.
Step 4 :The solution to the system of equations is \(x = 45\) and \(y = 46\).
Step 5 :So, the final answer is: There are \(\boxed{45}\) dimes and \(\boxed{46}\) nickels in the bag.