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 ?

(In reply to easy way to solve this type of problem by Jon)

Unless I misunderstand you, this logic is flawed, or your post is incomplete. If I simply pick an envelope to be true and look at that only, then results would be as follows: True envelope/formula envelope--1/2,2/3,3/1
all envelopes could be true and this would be inconclusive, you had to look further to see that only 2/3 woulb de the possible solution==>it is not as easy as you would make it out to be. I do believe however that you came to the correct conclusion.

Posted by john on 2003-04-12 15:38:49