Puzzle Thread Answers

[new_trader]

Might be good to have a seperate thread:
Post your answer here and a link to it in the Puzzle thread

 

[new_trader]

The question you ask one of the men is:

"If I were to ask the other man which door goes to heaven, which door would he pick?"

Go through the other door.

 

[firewalker99]

Might be good to have a seperate thread:
Post your answer here and a link to it in the Puzzle thread

Yes good idea. Perhaps there should be some sticky or link post in the other thread...

 

[Pat494]

The question you ask one of the men is:

"If I were to ask the other man which door goes to heaven, which door would he pick?"

Go through the other door.

well done !!

 

[Pat494]

The answer to post 155

Louise Archer will make the chocolate cake.
Julie Bowness will make the coffee cake.
Kay Cook will make the plain cake.
Mary Dancer will make the vanilla cake.

:smart:

 

[blackcab]

Answer to 133:

On a wall are 3 standard on/off switches. One (and only one) controls a light bulb inside a light-tight, well-insulated closet. The other two switches do nothing. You can only open the closet door once, and cannot touch/change any switches after the door is open (or re-closed, for that matter). Damaging or disassembling the door, walls, or switches is against the rules.

Within these constraints, can you determine with certainty which switch controls the light bulb?

Turn on switches 1 and 2. Wait a few minutes. Turn switch 2 back off. Go into the closet and:

Bulb is on = it was switch 1
Bulb is off but hot = it was switch 2
Bulb is off and cold = it was switch 3

That's a good one.

 

[firewalker99]

Answer to question from post #164 (hourglass problem):

See attached PDF.

 

[firewalker99]

Answer to question from post #158 (3 houses problem aka 3 utilities problem).

See here:

Math Forum: Ask Dr. Math FAQ: Three Houses, Three Utilities

Especially for PKFFW: instead of folding a paper... just continue your lines on the other side. After all, a piece of paper is 3D too

 

[PKFFW]

Here's my answer to the hourglass one.........not sure if it's cheating and probably wrong anyway since there would be no way to do it "perfectly" so to speak.

1: Mark a line at the sand height on the 4 minute hourglass when the sand is all in the bottom.
2: Open the hourglass and tip out the sand.
3: Open the 7 minute one and pour 4 mins worth of sand into 4 min glass.
4: You are left with 3 mins worth of sand in 7 min glass.
5: Tip 7 min glass over and allow sand to run to bottom.
6: Repeat step 5
7: Repeat step 5


Cheers,
PKFFW
P.S: if it's wrong I will continue to work on it

 

[firewalker99]

Here's my answer to the hourglass one.........not sure if it's cheating and probably wrong anyway since there would be no way to do it "perfectly" so to speak.

1: Mark a line at the sand height on the 4 minute hourglass when the sand is all in the bottom.
2: Open the hourglass and tip out the sand.
3: Open the 7 minute one and pour 4 mins worth of sand into 4 min glass.
4: You are left with 3 mins worth of sand in 7 min glass.
5: Tip 7 min glass over and allow sand to run to bottom.
6: Repeat step 5
7: Repeat step 5


Cheers,
PKFFW
P.S: if it's wrong I will continue to work on it

Glad you've given this one a try, despite me posting the answer two posts ago.

I must commend you on your creative solution. It's a good one, but unfortunately you're not allowed to open any of the hourglasses.

Nice try though

 

[PKFFW]

I figured as much.

About the houses and utilities I remember now why I originally put it aside........it was giving me the sh*ts something cronic! haha

I'm starting to think it can't be done and I know that if it can be done then I'm not smart enough to do it! haha

Going to look at the answer now.

Cheers,
PKFFW

 

[new_trader]

Hour Glass Timer

I have not looked at the answer:

Start:

1) Turn 4 and 7 over at the same time.

2) When 4 runs out, turn 4 & 7 over again (Total time elapsed is 4 min at this point. The 4 has 0 min remaining and the 7 has 3 min remaining)

3) After 3 minutes, the 4 has 1 min remaining and the 7 has 0 min remaining (Total time elapsed is 7 min at this point)

4) Turn both over. After 1 minute, the 4 has 0 min and the 7 has 6 min remaining ie/ 1 minute worth of sand has fallen. (Total time elapsed is 8 min at this point)

5) Turn the 7 back over until it is at 0 which will take 1 minute. Total elapsed time is now 9min.

 

[PKFFW]

I think you are on the right track N_T but I think you just didn't write it down right. At least that or I'm reading your answer wrong. If you flip both back over in your step 2 the 7 min glass will now have 4 mins in the top to run as 4 mins will have fallen to the bottom while the 4 min glass was running out.

Here's what I got.(btw, I hadn't looked at your answer till just now)

1: Start both timers
2: When 4 has run out immediately turn it back over and let 7 keep running
3: When 7 runs out 4 has 1 min left to go(elapsed time is 7 mins of course)
4: Immediately flip 7 over and let 4 continue.
5: When 4 runs out 7 will have 1 min of sand in the bottom(elapsed time 8 mins)
6: Flip 7 back over and let the 1 min in the bottom(now in top) run out.
7: Elapsed time 9 mins

cheers,
PKFFW

 

[new_trader]

Utilities to houses

My answer below:

 

[firewalker99]

I have not looked at the answer:
2) When 4 runs out, turn 4 & 7 over again (Total time elapsed is 4 min at this point. The 4 has 0 min remaining and the 7 has 3 min remaining)

Small error in (2), you have to let 7 running instead of turning over.

I think you are on the right track N_T but I think you just didn't write it down right. At least that or I'm reading your answer wrong. If you flip both back over in your step 2 the 7 min glass will now have 4 mins in the top to run as 4 mins will have fallen to the bottom while the 4 min glass was running out.

That's right, good one!

 

[new_trader]

Small error in (2), you have to let 7 running instead of turning over.


That's right, good one!

Yes, I did it correctly on paper but it got corrupted during the upload

Re Houses: I was thinking too theoretically...I like the solution. I did think about warping the paper but wasn't sure it was allowed.

 

[new_trader]

http://www.trade2win.com/boards/foyer/22827-puzzles-18.html#post427148

I'm convinced it has something to do with the way the pieces are redrawn. I am going to try and solve it at work using autocad on Sunday...too lazy to try on paper.

 

[trendie]

http://www.trade2win.com/boards/foyer/22827-puzzles-18.html#post427148

I'm convinced it has something to do with the way the pieces are redrawn. I am going to try and solve it at work using autocad on Sunday...too lazy to try on paper.

its a weird one!

the orange block = 7 squares
light green block = 8 squares
green triangle = 5 squares ( (5 x 2) / 2)
red triangle = 12 squares ( (8 x 3) / 2)

total surface area = 7 + 8 + 5 + 12 = 32 squares

big triangle = 32.5!!! ( (13 x 5) / 2)
I dont understand how the big triangle surface area is 0.5 square bigger than the smaller pieces added together.

Am I making false assumptions about the surface area of the triangles? (Length x Height / 2) ??

 

[firewalker99]

http://www.trade2win.com/boards/foyer/22827-puzzles-18.html#post427148

I'm convinced it has something to do with the way the pieces are redrawn. I am going to try and solve it at work using autocad on Sunday...too lazy to try on paper.

its a weird one!

the orange block = 7 squares
light green block = 8 squares
green triangle = 5 squares ( (5 x 2) / 2)
red triangle = 12 squares ( (8 x 3) / 2)

total surface area = 7 + 8 + 5 + 12 = 32 squares

big triangle = 32.5!!! ( (13 x 5) / 2)
I dont understand how the big triangle surface area is 0.5 square bigger than the smaller pieces added together.

Am I making false assumptions about the surface area of the triangles? (Length x Height / 2) ??

Hi guys, this is the answers thread though... I was going to post the answer here but I'll wait some more. The other thread is where the discussion should take place. I'm going to reply to your questions there.

 

[dick_dastardly]

Hey ! hang on a minute, something's not quite right here !

Are my eyes deceiving me ?

The hypotenuse on the upper triangle looks ever so slightly concave and the lower one looks convex.



dd