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Posted: 1/8/2005 10:51:13 PM EDT
You are a veterinarian. You have purchased a large balance scale on e-bay, but no weights were included. You want to use the balance scale to weigh animals. Assume the weight (in pounds) of every animal is an integer value less than 100.

A friend tells you that Balance Scale Weights R Us is a good place to purchase weights for balance scales. You visit BSWRU and talk to Rico, the mathematician turned weight salesman. Sensing that you're up to a unique challenge, he offers you two deals:

1. He has a standard weight set containing the following weights: 1, 1, 1, 1, 5, 10, 20, 20, and 50 pounds. He will sell this to you for $X.

2. Alternatively, he will custom-make a set of magical math weights.

Here's how the math weights work:
Rico will sell you a combination of numbers and mathematical symbols. Then, he will combine them however you like and magically turn them into weights equal to the numerical answer. For example, if you buy a "7", a "2", and a "^" Rico could use them to create a 128-pound (2^7) or 49-pound (7^2) weight. However, once a weight is created, you are stuck with it. You can't uncombine or add to the formula.

Rico has plenty of symbols, but he is in short supply of numbers. In fact, he only has 9s. Here are the prices for his numbers and symbols:

Each "9" costs $1.00.
Each simple arithmetic expression (+,-,*,/) costs $0.25.
His other arithmetic expressions (!,sqrt,^) cost $0.50 each.
Parentheses are free.

You're not exactly a penny-pincher, but you're intrigued by Rico's challenge. You want to have enough weights to be able to be able to calculate the exact weight of any animal less than 100 pounds. (Remember they all have integer weight values.)

What value of X makes the two alternatives equal?
Link Posted: 1/8/2005 10:55:25 PM EDT
[#1]
Someone should beat you with a textbook.
Link Posted: 1/8/2005 10:58:23 PM EDT
[#2]
Been eating beef? Can you say "Mad Cow"
Link Posted: 1/8/2005 11:01:13 PM EDT
[#3]
D. All of the above
Link Posted: 1/8/2005 11:02:34 PM EDT
[#4]





That's why I dropped out of  math, they started mixing in the alphabet!!
Link Posted: 1/8/2005 11:04:15 PM EDT
[#5]




Crap. I tried...I f-ing tried to get this..God damn
Link Posted: 1/8/2005 11:06:04 PM EDT
[#6]
Link Posted: 1/8/2005 11:09:44 PM EDT
[#7]
0
Link Posted: 1/8/2005 11:33:24 PM EDT
[#8]
It's late.

X=$43.00
Link Posted: 1/8/2005 11:44:21 PM EDT
[#9]

Quoted:
Someone should beat you with a textbook.



LOL.

There's a reason I failed Algerbra 2.
Link Posted: 1/9/2005 12:03:20 AM EDT
[#10]
Just fooing around I came up w/ x = $32.50 $27.25
Link Posted: 1/9/2005 12:03:40 AM EDT
[#11]

Quoted:

Quoted:
Someone should beat you with a textbook.



LOL.

There's a reason I failed Algerbra 2.



Algebra  

I hate math. My worst subject.
Link Posted: 1/9/2005 12:09:33 AM EDT
[#12]

Quoted:
Just fooing around I came up w/ x = $32.50



Nice try.... but no, it can be done with less than $32.50!

Any other guesses?
Link Posted: 1/9/2005 12:15:43 AM EDT
[#13]
Ya know what I think...

I think someone surfed ARFCOM a little too long and did not get his math homework done, so he posts it here hoping that some one will solve it...because why would any one, normal, person want to post teasers like that for fun?

Don't worry...I've done it too.  
Link Posted: 1/9/2005 12:15:46 AM EDT
[#14]

Quoted:

Quoted:
Just fooing around I came up w/ x = $32.50



Nice try.... but no, it can be done with less than $32.50!

Any other guesses?



See my edited answer.
Link Posted: 1/9/2005 12:24:32 AM EDT
[#15]
I'm at x=33.  I must be missing something.

Steve
Link Posted: 1/9/2005 12:32:26 AM EDT
[#16]

Quoted:
I'm at x=33.  I must be missing something.

Steve



Hint: you don't actually need, 1, 1, 1, 1, 5, 10, 20, 20, and 50.
Link Posted: 1/9/2005 12:39:31 AM EDT
[#17]
I'm down to x=16

Steve

ETA:

          Value    Quantity   Price  Total

9/9         1              2         2.25  4.50
sqrt(9)   3              2         1.50  3.00
9            9              2          1.00  2.00
9+9       18            2          2.50  5.00
9!          45            1          1.50  1.50
                                                  16.00
Link Posted: 1/9/2005 12:41:57 AM EDT
[#18]

Quoted:
Hint: you don't actually need, 1, 1, 1, 1, 5, 10, 20, 20, and 50.


edited do to this info
Link Posted: 1/9/2005 12:44:07 AM EDT
[#19]
Link Posted: 1/9/2005 12:45:22 AM EDT
[#20]
Alright, I am down to $16.25 $14.25!

back to the abbacus!

shit
Link Posted: 1/9/2005 12:45:58 AM EDT
[#21]
Link Posted: 1/9/2005 12:47:17 AM EDT
[#22]
doh!  right, that's 9*8*7...

Dumass me

Steve
Link Posted: 1/9/2005 12:51:30 AM EDT
[#23]
Now i'm back up to x=18.50.


Steve
Link Posted: 1/9/2005 12:51:55 AM EDT
[#24]
Link Posted: 1/9/2005 12:58:43 AM EDT
[#25]
Alright, I am at $17. 50 or $18.50 depending on the answer to a question I have.
Link Posted: 1/9/2005 1:04:10 AM EDT
[#26]
Link Posted: 1/9/2005 1:04:21 AM EDT
[#27]
Isn't 42 the answer to life, the universe and everything?
Link Posted: 1/9/2005 1:09:42 AM EDT
[#28]
Link Posted: 1/9/2005 1:18:12 AM EDT
[#29]
SOLUTION


We need only buy the integer powers of 3, from which we can add and subtract to form other numbers, by putting weight on the same or opposite sides of the scale respectively.
This is also efficient because of their relationship to the number 9.


1=9/9 --> $2.25
3=sqrt(9) --> $1.50
9=9 --> $1.00
27=9xsqrt(9) --> $2.75
81=9x9 --> $2.25
______________________
Total: $9.75
Link Posted: 1/9/2005 1:20:17 AM EDT
[#30]
Link Posted: 1/9/2005 2:03:06 AM EDT
[#31]

Quoted:
SOLUTION


We need only buy the integer powers of 3, from which we can add and subtract to form other numbers, by putting weight on the same or opposite sides of the scale respectively.
This is also efficient because of their relationship to the number 9.


1=9/9 --> $2.25
3=sqrt(9) --> $1.50
9=9 --> $1.00
27=9xsqrt(9) --> $2.75
81=9x9 --> $2.25
______________________
Total: $9.75




It's bad enough you give us an math problem at 4:00 am.  You didn't have to go and make it a trick question too!

Steve

Link Posted: 1/9/2005 3:45:06 AM EDT
[#32]

Quoted:
Someone should beat you with a textbook.



+1
Link Posted: 1/9/2005 4:14:03 AM EDT
[#33]
Gimme that book, when you are done!
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