SOLUTION: There are two boxes labeled “A” and “B.” Note on the box “A” reads: The note on the box “B” is true and gold is in the box “A.” Note on the box “B” reads: The note on the box “A” i

Algebra.Com
Question 129798: There are two boxes labeled “A” and “B.” Note on the box “A” reads: The note on the box “B” is true and gold is in the box “A.” Note on the box “B” reads: The note on the box “A” is false and gold is in the box “A.” You have only one chance to open a box to get gold. Which box would you open and why?

Answer by solver91311(24713)   (Show Source): You can put this solution on YOUR website!
I'm going to establish some symbology for this discussion.
is the note on A, is the note on B, is "the gold is in box A", is "the gold is in box B"

Also, since I can't figure out how to render a vinculum on this system, I'm going to denote the idea of 'Not' by prefacing the above symbols with an . = 'not the note on A' which is equivalent to 'the note on A is false' Also & means 'and', v means 'or', T means True, and F means False. And lastly, a => b, means 'if a then b'

&

&

Let's begin by assuming .

If then , but if then . This is a contradiction. Therefore

=> v

=> . Let's save this result for later.

=> (not not ) v

We have already proven , so for to be true, must be true, and, again, => .

Therefore, the gold is in Box B.

RELATED QUESTIONS

Hello here is a word problem i can not figure out called It's in a Box!: There are two (answered by jim_thompson5910)
the cost of 5 boxes of envelopes and boxes of note paper is $25.95. Two boxes of... (answered by stanbon,solver91311)
There are 18 oranges in box a and 36 in box b what is the ratio of the orange in box a to (answered by ikleyn)
A box A contains 4 gold rings and 3 diamond rings. A box B contains 2 gold rings and 5... (answered by ikleyn)
An empty box with top, bottom and four sides, is a two and a half-foot cube. It is... (answered by KMST)
There are some apples in three boxes. A, B and C. 40% of the number of apples in Box A is (answered by josgarithmetic)
Hi there are 5 times as many strawberries in box a than in box b. There are 60 more... (answered by souvik2212das,josgarithmetic)
The cost of 5 boxes of envelopes and 5 boxes of note paper is $ 25.95. Two boxes of... (answered by ewatrrr)
On a table are two boxes. One box contains only 50c coins and the other contains only 20c (answered by josgarithmetic)