Author |
Topic: Designing a watertank (Read 372 times) |
|
JocK
Uberpuzzler
Gender: 
Posts: 877
|
 |
Designing a watertank
« on: Sep 3rd, 2005, 7:57am » |
 Quote  Modify
|
You are a junior engineer in a metal manufacturing company. On a Friday afternoon you are called into the managing director's office.
When you enter the director's office, you find the director in discussion with the senior engineer.
"Listen" says the director, "I heared you are a bright young guy, surely you can help us with the following".
"We have received a large order for watertanks. Big business, a total of 15,000 tanks. These tanks should each contain one cubic metre of water. Now, we have plenty of supply of large steel plates. In fact, the cost of the steel or the size of the plates is not the issue here. The issue is that welding the steel plate such that the tanks are watertight is damn expensive. And that welding cost is a cost per metre. For 15,000 tanks it adds up quickly if we don't carefully design a tank that can be manufactured from steel sheets using a minimal welding length."
"What would you.."
Before the director finishes his sentence you interupt him enthusiastically:
"I know exactly what we need to do! I saw it on a math forum: you cut two identical more-or-less oval-shaped plates. These can be welded together with a welding length in metres that is the third root of 263.4... That is... uhhh... 6.41 metres!"
"Ha, ha!" laughed the senior engineer, what do they teach you guys at school these days?"
"I just explained that you can weld a box-shaped tank of 2 x 1/sqrt(2) x 1/sqrt(2) metre with exactly 6 metres of welding! That is 41 cm less!"
You are puzzled. What did you do wrong?
Both men look at you, awaiting your reaction.
Then you realise what design is behind the 6 m claim. You turn to the director and reply confidently:
"Now that I think about it, I am sure I can improve upon the box design by more than it improved upon the double oval...!"
"Well, well..." says the director, "Less than 5.59 metres of welding.... you better explain right here and right now what your design looks like!"
http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_har d;action=display;num=1124994244
|
| « Last Edit: Sep 3rd, 2005, 9:26am by JocK » |
 IP Logged |
solving abstract problems is like sex: it may occasionally have some practical use, but that is not why we do it.
xy - y = x5 - y4 - y3 = 20; x>0, y>0.
|
|
|
towr
wu::riddles Moderator
Uberpuzzler
Some people are average, some are just mean.
Gender:
Posts: 13730
|
|
Re: Designing a watertank
« Reply #1 on: Sep 3rd, 2005, 2:26pm » |
Quote Modify
|
A shame they never heard of pressing plate steel into shape. They could safe a bundle on welds.
|
|
IP Logged |
Wikipedia, Google, Mathworld, Integer sequence DB
|
|
|
|
RIDDLES SITE
WRITE MATH!
Home 
Help 
Search 
Members 
Login 
Register
Reply
Notify of replies
Send Topic
Print