What’s the domain of the function?

At dinner, 2/5 of the people had fish and 1/3 had chicken. if everyone else had lamb, what fraction of the people had lamb? and if 40 people had lamb , calculate the total number of people at the dinner.

In the diagram, the ratio of ab to ae is (1/2) . what is the ratio of the length of to the length of ?

Qrst is a parallelogram. determine the measure of ∠q pls