Excel / Libre Office Calc: Taking the average of a multiplication

I have three rows in Libre Office I want to divide the third row by the second and multiply by the first row. After that I want to take everything and take the average. How do I do all that in one formula?

I tried

        =MITTELWERT((K23:N23)/(K22:N22))

(MITTELWERT mean average) but that did not work yet. What to do?