If this is a riddle. I've heard it phrased that "one of them is not a nickel", in which case the other coin is a nickel.

One quarter & one nickel

This was on Scrubs when JD asked the janitor a riddle so he'd stop doing everything he does to him.

The answer is a quarter and a nickle. (one coin isn't a nickle, the other one is)

The answer is a quarter and a nickle. (one coin isn't a nickle, the other one is)

1 coin is not a nickel, but the other one is.

The other one is a nickel. So one is a quarter and the other is a quarter, and so one of them is a quarter and the other one is a nickel.

One isn't a nickel but the other one is so one is a quarter and one is a nickel.

From 1875-1878 there was a 20 cent coin. But it was too similiar in size to a quarter, so they didn't catch on. So the answer could be a 20 cent and a 10 cent coin.