Let x be the number of dimes Chelsea has; since she has 6 more nickels than dimes this means that the number of nickels can be express as:
Now, we know that in total she has 2.55 and that the dimes are worth $0.1 and the nickels are worth $0.05, then we have the equation:
Solving for x we have:
Hence Chelsea has 15 dimes.
To determine the number of nickels we plug the value of x in the expression for the number of nickels, then we have:
Hence Chelsea has 21 nickels
Therefore we conclude that Chelsea has 15 dimes and 21 nickels.