### Brain Teasers

# Ill-Equipped Laboratory

You are working in a lab and you need to prop up a beaker of water so that its base is exactly 17" above the table (don't worry about why). Besides the beaker, the only objects in the lab are a yardstick and five phone books, at 1", 3", 4", 5", and 6" thick each.

How do you arrange the books so that you can prop up the beaker at the correct height?

How do you arrange the books so that you can prop up the beaker at the correct height?

### Hint

If you're stuck then you're forgetting something very important. Remember - these are BOOKS, not blocks of wood.### Answer

Simply pile up all of the books except the 1" one. This will give you 18 inches. Open the top book, turning 1" worth of pages. Use the yardstick to verify the height.If you want to be really technical, you should actually open the bottom book, because the bulge caused by the open book will then be flattened by the other books.

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## Comments

I'm sure that lots of you won't consider this to be a very difficult teaser, but the truly sad part about it is that I found myself in this exact situation recently and for a frustrating five minutes tried every combination of books that I could manage. Only then did my partner turn to me and say "why don't you just open the top book a little?" So having said that, I will kindly ask that if this stumps any of you for a while, please let me know so that I can feel less alone in my shame. ;)

well, i'll admit, it took me a few minutes! and then, i didnt open the book, i ripped pages out! hehe

Yea, it took me a few minutes as well. First I played with the numbers a bit in my head until I was sure it could not be done by picking the right ones then I thought about breaking the ruler up into small peices and stacking them up to make an inch. Thats when it hit me that a book could be opened so as to reduce its thickness by an inch and save the ruler. I thought it was a good riddle, but you should look into getting some stands with vertical metal rods and sliding clamps so that you can always set things up easily in the future.

Good puzzle, nice solution. I

came up with an alternate solution

that's probably not as practical: Stack the

6, 5 and 4 inch books in a stack.

Put the 1 inch and 3 inch books side

by side crosswise on the top (making

two surfaces 16 and 18 inches above the table).

Put the yardstick diagonally from the

1 inch book to the edge of the 3 inch book.

Balance the beaker (carefully!) on the yardstick

at the

halfway point between the start of the ruler

and where it meets the 3 inch book. That

should be 1 inch above the 1 inch book, so 17

inches above the table. Hope the

whole thing doesn't come crashing down, spilling

water everywhere.

came up with an alternate solution

that's probably not as practical: Stack the

6, 5 and 4 inch books in a stack.

Put the 1 inch and 3 inch books side

by side crosswise on the top (making

two surfaces 16 and 18 inches above the table).

Put the yardstick diagonally from the

1 inch book to the edge of the 3 inch book.

Balance the beaker (carefully!) on the yardstick

at the

halfway point between the start of the ruler

and where it meets the 3 inch book. That

should be 1 inch above the 1 inch book, so 17

inches above the table. Hope the

whole thing doesn't come crashing down, spilling

water everywhere.

To electrojohn: yes, we normally have a nice little scissor-lift to properly set the height, but alas, things in our lab have a habit of "disappearing" and never returning. To Dewtell: It's an interesting solution, but I think that if my advisor walked in while I was balancing a beaker on a diagonally-propped yardstick, he might not be all that impressed. (although it would certainly be a good argument for getting a new scissor-lift)

I thought the point was to use all the books, and I also did it without the yardstick. answer???...

If you use all books and were to turn the 4" book to the very middle page, you would have 17". Took me less than a minute ;)

If you use all books and were to turn the 4" book to the very middle page, you would have 17". Took me less than a minute ;)

I kinda came up with the same solution as meaix there, only I had to use the measuring stick, as any anomoly in the thickness of individual pages, or whatever, could cause an error in measurement.

I was close. I said open the 4" book in half. Then you would have one and two and three and five and six inches. You're answer works too.

you could partially open all of the books and measure each, ensuring that the ttoal = 17.

Bobbrt, are you a scientist? As in, your job? By the way, that teaser was easy. It just takes a bit of logic. If you are familliar with this kind of teaser (like me) then it is very simple.

There are lots of ways to solve this teaser if you worry about the fine details. My only intent with submitting this teaser was to see how many people would try to come up with just the right combination of books, when it really makes no difference at all how thick each book is as long as you have more than 17" total. ...And Doggy, I'm a Chemical Engineering graduate student working on my PhD. I'd tell you what my research was about, but it would just put you to sleep.

Ah! A budding Anaesthetist, eh!

I liked this one... and I love reading all of the comments even more... it fascinates me how our brains work and how they even come up with answers to problems in the first place -- the very fact that we all came up with multiple correct answers is very cool to me... I don't know if I'm explaining myself well! lol

Took me a while,but I got it.

I got TECHNICAL!

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