There is no combination of two American coins that add up to 55 cents without the use of a nickel. However, a 50-cent piece and a nickel add up to 55 cents.
This question is a popular riddle used to challenge people to name two coins totaling 55 cents. In the riddle, the solution is that a 50-cent piece and a nickel sum up to 55 cents. This riddle is targeted towards young children who are learning financial basics. It is also used as a brain teaser to engage in witty banter. This answer is not meant to be a challenge for most people with basic knowledge of American currency.