There are three envelopes and exactly two statements are written on each of the envelopes. The statements on one of the envelopes are BOTH TRUE, the statements on the other envelope are BOTH FALSE and the remaining envelope has ONE TRUE and ONE FALSE statement. Here is what is written on the three envelopes:

First Envelope:
(a)The formula is not in here.
(b)The formula is in Envelope 2.

Second Envelope:
(a)The formula is not in Envelope 1.
(b)The formula is in Envelope 3.

Third Envelope:
(a)The formula is not in here.
(b)The formula is in Envelope 1.

Which envelope contains the formula ?

There are just 12 possible situations, so it is easy to check thru them: The formula is in envolope 3, with:

Envelope 1: (a) True  (b) False

Envelope 2: True

Envelope 3: False

 

Posted by FrankM on 2008-04-06 09:37:32