Propositiones ad Acuendos Juvenes/Problems/6 - De Duobis Negotiatoribus C Solidos Communis Habentibus/Historical Note

== Historical Note on by : Problem $6$: De Duobis Negotiatoribus == According to, this is the first appearance of the type of problem known as the Applesellers' Problem, also known as the missing penny or marketwomen's problem.

It hinges on the fact that a common mean is erroneously being calculated of $2$ for a monetary unit plus $3$ for a monetary unit equals $5$ for $2$ monetary units.

goes on to remark that, while this problem appears everywhere in European puzzle-books since its appearance here, he has never seen a non-European version.

However, claims in his  that it appears in 's, which dates from c. $850$. However, this has not been corroborated.