A52 year-old father has a son and a daughter. the son is twice as old as the daughter. in 4 years the sum of all their ages will be 100. how old are the two siblings now? (rsm problem)

Which property is illustrated by the following statement? if hxa rgi, then rgi hxa.

You have 3 boxes, one "strawberries"; one "mentos" and one "mixed".but you know that all the labels are in incorrect order .how do you know witch is witch?

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."