How do I calculate the average Z molar mass, 1/n (Summation) of n*M given this data: (alternate equation: MZ=Summation N*M^3/Summation N*M^2)

Question

(Ave molar mass, mass of sample):

(7.5,9.6) , (12.5,8.7), (17.5, 8.9), (22.5, 5.6), (27.5, 3.1), (32.5,1.7)

mili moles for repective numbers: 1.3,.7,.51,.25,.11,.052 TOTAL: 2.92

I don't know what numbers to sum

Answer 1

I don't understand the question. Perhaps another tutor will.

Answer 2

thanks for taking a look! :)