You have two US coins in your hand which total fifty-five cents One is not a nickel What are the coins?

It is impossible, since no coin + half dollar = 5 cents besides a nickel. 1,5,10,25,50, $1 are the coin denominations of today. However, if you used a half dime, it could technically work out, as 50 half dollar + 5 half dime = 55 cents. A half dime is a coin worth 5 cents. A nickel today, is just a name for 5 cent coins. For example cent or penny is a name for a 1 cent piece as a dime is a name for a 10 cent piece etal. Todays nickel is made of copper and silver.