I am not going to bother with the transcription but just do the translation:
Offenbach on the Main the 17th November 191(o) (?)
Mr. Paul Scherpenbach
In the agreed upon and notarized purchase and rental contract between us from the 11th of this month, the annual rent price was mistakenly set at 80 Marks while in reality it should have been 200 Marks.
I obligate myself herewith to pay the intended rental price of 200 Marks in increments of 50 Marks at the specified periods noted in the contract.
The widow [of] Gustav Peters
hope this helps,