Using relational algebra not SQL. Thx in advance!

Consider the following relational database that stores information about bars and customers: Drinker (name, address) Bar (name, address) Beer (name, brewer) Frequents (drinker bar, times a week) Likes (drinker, beer) Serves (bar, beer, price) (5 points) Find all drinkers who frequent every bar that serves some beers they like. Q1.6. Q1.7. (10 points) Find those drinkers who enjoy exactly the same set of beers as Amy