Petra has 49 blue marbles and two red marbles. How many marbles must Petra remove so that
90 % of her marbles are blue?
(A 10
(B) 15
(C) 20
(D) 30
(E) 31

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."

What is the area of a triangle with vertices at (-3 3) (-3,2) and (1,2)?

Pls never taught i’m really confused and i rlly need