How To Calculate The Number Of Complaints Per 1000 Members. Total Membership Is 2800 And Total Complaints Received Is 33?

2800 = 2.8*1000, so you know there are 2.8 thousand members

(complaints)/(thousand members) = (33 complaints)/(2.8 thousand) = 33/2.8 = 11.786

You are receiving about 11.8 complaints per thousand members.