Tom bought six CDs that were each the same price including sales tax he paid a total of $67.80 each CD has a tax of $.50 what was the price of each CD before tax

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?