a maths question for u to try.kindly tag me if u have the ans.(:

John bought a toy car at $18.He sold it to Bala at $21,Bala gave him a one-hundred dollar note.John didn't have change so he change it with Ken.Ken gave him a smaller change and John gave Bala his change,$79.After that,Ken found out that the one-hundred dollar note is fake and ask John for another one-hundred dollar note,How much money John lose?