Put on your thinking caps.

[mamoeba]

I came across this interesting little puzzle here:

Suppose a teacher announces to her class one Friday afternoon that she will give a surprise quiz sometime during the following week. Her class meets five days a week (poor class), so the test could be on Monday, Tuesday, Wednesday, Thursday, or Friday. But it can't be on Friday - by Thursday night

Comments

[anonymous]

Is it really a surprise test when you are told that it is coming?
K
just wondered....

[mamoeba]

Well, that's a good point. The whole exercise can be subverted right from the start if you think of it that way. However, I have had teachers do something like this, ie. give us a range over which there will be a test. So I take "surprise test" in that sense to mean "a test which you will not be told about the night before it happens". I think the idea is to encourage storing the info in our long term memories, rather than cramming and then forgetting it all a day later.

[anonymous]

what if the test was given every day of the particular week?
so on monday ..you get a pre-warned "surprise test", and so that night you go home thinking "..well... at least that's done with.."
but then you go in on tuesday and there's another test oohhh noo.
then it's really a surprise!
even worst, what if it happened the next day too.

this is turning out to sound like a bad dream