How do you separate a fine powder consisting of aluminum soda cans, steel cans, milk jugs, and soda bottles?

rate of change

Explanation:

To calculate the average atomic weight, each exact atomic weight is multiplied by its percent abundance, then add the results together and round off to an appropriate number of significant figures.  So according to what's given, the average atomic mass of element M should be (23.9850*0.7899)+(24.9858*0.1000)+(25.9826*0.1101)=24.30