If the range of a normally distributed data set is 25, what's a reasonable estimate for the standard deviation

Which is an equation for the nth terms of the sequence 12,15,18,21

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."

Which equation shows the quadratic formula used correctly to solve 5x2 + 3x -4 0 for x? cos -3+ v (3) 2-4() 2(5) 3+ |(3)² +4() 205) 3+ (3) 2-4() -3+ v (3)² +4()