Suppose you meet a person inhabiting this planet and they ask you “Am I a Crick?" What would you conclude?
You meet two friends, Katja and Anja. Katja once asked Anja “Is at least one of us a Goop?"
What kinds are Katja and Anja?
You later learn that there is exactly one wizard on this planet. You would like to find out who that is.
You meet an alien called Andrew. He asks you “Am I the kind that could ask whether I am not the wizard?"
Do you have enough information to tell for sure who the wizard is by now?
You meet another alien, whose name is Teddy. He asks you “Am I the kind who could ask whether I am a Goop?"
Can anything be deduced about Teddy?
You meet a couple, Dan and Daisy. Dan asks Daisy “Are you the kind who could ask me whether I am a Crick?"
What can be deduced about Dan and Daisy?
You meet an alien called Bobby. He asks you “Am I the kind who could ask whether the wizard is the kind who could ask whether I am the wizard?"
Do you now know for sure who the wizard is?
You then meet a strange alien who asks you “Am I the kind who could ask you the question I am now asking?"
What can be said about her?
You meet three friends: Alex, Bernie and Carol. Alex asked Bernie “Are you the kind who could ask Carol whether she is the kind who could ask you whether you two are of different kinds?".
You might realise that it is only possible to deduce the kind of one of the three friends. Which one and are they a Crick or a Goop?
You meet an alien called Charlie. He asks you “Are the wizard and I the same kind?"
Who is the wizard?
a) Mr Smith has seven children. He wants to send three of them to run some errands on a Saturday. We will send the first one at 1pm, second one at 2pm and the third one at 4 pm. In how many ways can he choose them?
b) The children decided to actually go run all the errands together at 1pm, instead of going separately. Knowing this, in how many ways can Mr Smith select three of them to run the errands?