FOR EXAMPLE You meet three islanders named Ellis, Farin, and Gobi. They all know what each other is (a knight, knave or joker) and make the following statements:If exactly one of them is a joker then One of them is a knight Since exactly one of them is a joker, and they all accuse different people of being jokers, then the joker is lying. If the joker were telling the truth, then they would claim that they themselves are the joker, which none of these three are doing. Given this, one of them is telling the truth. For instance, suppose that Ellis is the Joker, then Gobi is telling the truth. Or you can suppose that Farin is the joker, in which case Ellis is telling the truth. Same thing with Gobi. This person telling the truth can't be a joker since all the statements accuse other people of being jokers and, again, a joker telling the truth this once would say that they, themselves, are the joker. So the truth-teller must be a knight. So one person is a joker, and at least one is a knight. The third person can't be a knight (they must be a knave), because the knight and the third person are saying that different people are jokers, which is impossible with only one joker. For instance, if Ellis is the joker, then Gobi is telling the truth (and is a knight), and Farin is lying (and is a knave. So, since there is only one truth-teller there must be only one knight
This arrangement is ethical as long as the engineer signs and seals each design segment only after it has been reviewed by an independent consulting engineer who specializes in the field which it pertains.<span> If what she was dealing is not her field of expertise, she needs to have the aid of independent engineer who can verify the work passed to her before she signs the design segment.</span>
The availability of many substitutes increases the elasticity of demand for a good. With the presence of substitutes the consumer has more options to seek out if there are price changes, therefore, the consumer is highly responsive to price changes and thus the elasticity of the demand curve is higher if there are many substitutes.
