In a class of 80 students, every student had to study mathematics or biology or both mathematics and biology ,If 65 students studied mathematics and 62.5% of teh class studies biology ,how many students studied both subjects

Asays "we are both knaves" and b says nothing. exercises 24–31 relate to inhabitants of an island on which there are three kinds of people: knights who always tell the truth, knaves who always lie, and spies (called normals by smullyan [sm78]) who can either lie or tell the truth. you encounter three people, a, b, and c. you know one of these people is a knight, one is a knave, and one is a spy. each of the three people knows the type of person each of other two is. for each of these situations, if possible, determine whether there is a unique solution and determine who the knave, knight, and spy are. when there is no unique solution, list all possible solutions or state that there are no solutions. 24. a says "c is the knave," b says, "a is the knight," and c says "i am the spy."

The collection of beautiful oil paintings currently on display at an art gallery well defined; set not well defined; not a set

I'm confused on how to solve the triangle. can someone me ?