CAN YOU ANSWER THIS QUESTION? (page 6)

OUTLAW

Terry..When will you give us the correct answer?..I`ve enjoyed this..I`ll check back tonight...OUTLAW

Terry

The sack of potatoes now weighs 50 lbs.
Originally, the 100 lb sack had 99 lbs (99%) water and 1 lb. potato. Potato does not evaporate, so the bag still contains 1 lb of potato. Therefore the 100 lb sack is now made up of 98% water and 2% potato. One pound is 2% of 50 lbs, therefore the bag now weighs 50 lbs.

I'm very impressed with you! You are correct!

If you have 100 of anything and the total of them weighs 100lbs. then notice:

1. Only one (1) of them is 1/100th of 100lbs and that means 1 is equal to 1 lb.

2. If, however, it takes 2 of them to equal 1 lb and you have 100 of these things (of which it takes 2 to equal 1 lb) then the total number of them can only weigh 50 lbs.

The fact that the sack of spuds is 2% potato means that it now takes 2% to equal the same one pound as before.

The only reason the original problem is difficult is because of the way people WANT TO THINK ABOUT THE PROBLEM.

We have a built-in PREJUDICE about how the outcome should look and this spoils our subsequent processing.

Above examples demonstrate that wrong procedures can still be logical and produce wrong answers.

For me, this is a good model of the metaphor of wrong-headed reasoning with excellent intelligence going awry.

Thank you!

Terry

We know there is 1lb of non-water in the sack, which now makes up 2% of the total. Therefore, the total weight is now 50lbs.

I'm impressed with the simplicity of your correct answer! Congratulations!

Gerard

100Lbs / 99% water so, final weigh if moisture is reduced to 98%?:
X=((100 Lbs) * 98%) / 99% = 98.99 Lbs
Somehow I don't expect this to be about the math but syntax. -Gerard
Thank you for a logical presentation of a WRONG answer!
Your process is impeccable. However, it is the wrong way about it.
Try again. -Terry

As I suspected, the challenge was not algebra but synthax. Good to use to illustrate preconceptions and interpretations.

Terry

Terry..When will you give us the correct answer?..I`ve enjoyed this..I`ll check back tonight...OUTLAW

50 lbs really IS the correct answer.

The 2% potato content still only weighs one pound. Consequently, the other units which add up to 100% have half the value they previously had when the potato content was 1%.

PopeOfEruke

This is the same problem exactly but for some reason a lot of people who get stuck with the potatoes can work this one out easily :

A room contains 100 people, 99% of which are male.

Some males leave the room.

A count is retaken and it is found that now 98% of the room are males.

How many people are now in the room??

I think why the potato problem is harder to visualize is that the water is *in* the potato, therefore it is much harder for the brain to see 2 separate entities, the "water" and the "potato starch" or whatever the heck you call the stuff in a potato that is not water.

With the room puzzle, the males and females are really separate entities to the brain and it's easier to visualize a number of men (the "water") leaving the room (the "potato") but the female contingent (the "potato stuff" staying behind.

Pope

Terry

I think why the potato problem is harder to visualize is that the water is *in* the potato, therefore it is much harder for the brain to see 2 separate entities, the "water" and the "potato starch" or whatever the heck you call the stuff in a potato that is not water.
With the room puzzle, the males and females are really separate entities to the brain and it's easier to visualize a number of men (the "water") leaving the room (the "potato") but the female contingent (the "potato stuff" staying behind.
Pope

And this is what fascinates me!

Problems aren't difficult for the mind to solve. Organizing "meaningfully" is the real problem. I think it has to do with our sloppy conceptual rigor.

We always go with the first and easiest conceptual mapping rather than a more deliberate and analytical one.

We "assume" too much.

funkyderek

Another one of similar vein:

You're at a party and you start to wonder if any two people there share a birthday. How many people would have to be at the party before it's more likely than not that there are two people with the same birthday? [They don't have to be born in the same year, just the same month and day. Leap years can be ignored.]

Terry

25?

CAN YOU ANSWER THIS QUESTION?

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