Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

techlover828

macrumors 68020
Jun 28, 2007
2,358
2
Maine
Can you prove which is larger, e^pi or pi^e, using properties of those numbers rather than simply computing the exponentials?

It's a real question, not a trick. I had this problem on a test. If only I could remember the answer!

e is smaller right? so e^pi would be larger.
 

fridgeymonster3

macrumors 6502
Jan 28, 2008
493
13
Philadelphia
Can you prove which is larger, e^pi or pi^e, using properties of those numbers rather than simply computing the exponentials?

I don't think your using the properties of those numbers since the properties are their actual values. If you use ln or maybe f(x) I think you can derive the answer. Not that I feel like doing the actual work, or taking the time to find the answer online :). But i think with the natural log you can show the reason behind one being bigger than the other.
 

Nermal

Moderator
Staff member
Dec 7, 2002
20,632
3,987
New Zealand
In a recent introductory offer, a special brand of brandy in a fanciful bottle was promoted at $120 per bottle. If the brandy itself cost $105 more than the container, how much was the empty bottle worth?
 

techlover828

macrumors 68020
Jun 28, 2007
2,358
2
Maine
In a recent introductory offer, a special brand of brandy in a fanciful bottle was promoted at $120 per bottle. If the brandy itself cost $105 more than the container, how much was the empty bottle worth?

I want to say 15 but there must be something more, obviously.

edit: does it have anything to do with you changing bottle to container in one sentence?
 

swiftaw

macrumors 603
Jan 31, 2005
6,328
25
Omaha, NE, USA
In a recent introductory offer, a special brand of brandy in a fanciful bottle was promoted at $120 per bottle. If the brandy itself cost $105 more than the container, how much was the empty bottle worth?

Logic would seem to indicate $7.50, but I'm sure I'm missing a trick somewhere.
 

Nermal

Moderator
Staff member
Dec 7, 2002
20,632
3,987
New Zealand
edit: does it have anything to do with you changing bottle to container in one sentence?

No. I'm quoting straight out of a book but the container and the bottle are the same thing.

I want to say 15 but there must be something more, obviously.

Logic would seem to indicate $7.50, but I'm sure I'm missing a trick somewhere.

Bingo. Swift got it right, but as you can see above, some people say $15!
 

fridgeymonster3

macrumors 6502
Jan 28, 2008
493
13
Philadelphia
In a recent introductory offer, a special brand of brandy in a fanciful bottle was promoted at $120 per bottle. If the brandy itself cost $105 more than the container, how much was the empty bottle worth?

I have to say $7.50 also

A = Brandy
B = Bottle

A = B + 105 (Brandy costs $105 more than Bottle)

$120 = (B+105) + B

B = $7.50
 

swiftaw

macrumors 603
Jan 31, 2005
6,328
25
Omaha, NE, USA
How about this one:

Three hotel guests stay together. They receive a bill for $30. They each put $10 on the table, which the bellhop collects and takes to the till. The cashier informs the bellhop that the bill should only have been for $25 and returns $5 to the bellhop in $1 bills. On the way back to the room the bellhop realizes that he cannot divide the bills equally between the guests. As they didn’t know the total of the revised bill, he dishonestly decides to put $2 in his own pocket and give each of the guests $1.
Now that each guest has been given a dollar back, each of them has paid $9. Three times 9 is 27. The bellhop has $2 in his pocket. Two plus 27 is $29. The guests originally handed over $30. Where is the missing dollar?
 

techlover828

macrumors 68020
Jun 28, 2007
2,358
2
Maine
How about this one:

Three hotel guests stay together. They receive a bill for $30. They each put $10 on the table, which the bellhop collects and takes to the till. The cashier informs the bellhop that the bill should only have been for $25 and returns $5 to the bellhop in $1 bills. On the way back to the room the bellhop realizes that he cannot divide the bills equally between the guests. As they didn’t know the total of the revised bill, he dishonestly decides to put $2 in his own pocket and give each of the guests $1.
Now that each guest has been given a dollar back, each of them has paid $9. Three times 9 is 27. The bellhop has $2 in his pocket. Two plus 27 is $29. The guests originally handed over $30. Where is the missing dollar?

that's a good one, I have no idea :confused:
 

fridgeymonster3

macrumors 6502
Jan 28, 2008
493
13
Philadelphia
How about this one:

Three hotel guests stay together. They receive a bill for $30. They each put $10 on the table, which the bellhop collects and takes to the till. The cashier informs the bellhop that the bill should only have been for $25 and returns $5 to the bellhop in $1 bills. On the way back to the room the bellhop realizes that he cannot divide the bills equally between the guests. As they didn’t know the total of the revised bill, he dishonestly decides to put $2 in his own pocket and give each of the guests $1.
Now that each guest has been given a dollar back, each of them has paid $9. Three times 9 is 27. The bellhop has $2 in his pocket. Two plus 27 is $29. The guests originally handed over $30. Where is the missing dollar?

you are doing some voodoo wording there aren't you :)
 

EricNau

Moderator emeritus
Apr 27, 2005
10,728
281
San Francisco, CA
How about this one:

Three hotel guests stay together. They receive a bill for $30. They each put $10 on the table, which the bellhop collects and takes to the till. The cashier informs the bellhop that the bill should only have been for $25 and returns $5 to the bellhop in $1 bills. On the way back to the room the bellhop realizes that he cannot divide the bills equally between the guests. As they didn’t know the total of the revised bill, he dishonestly decides to put $2 in his own pocket and give each of the guests $1.
Now that each guest has been given a dollar back, each of them has paid $9. Three times 9 is 27. The bellhop has $2 in his pocket. Two plus 27 is $29. The guests originally handed over $30. Where is the missing dollar?
There is no missing dollar.

You shouldn't be adding the $2, you need to subtract it. Remember, the total is $25, not $30. Therefore, each guest paid $9 x 3 = $27 - the stolen $2 = $25.

EDIT: Darn, too slow. I heard that one years ago, but it took me a minute to remember the answer!



Has anyone figured out this sequence yet?

Give the next two numbers in this sequence: 9, 10, 11, 12, 13, 14, 21, ...
 

Dros

macrumors 6502
Jun 25, 2003
484
1
A man hires you to tie a rope loop around the equator of spheres as an art project. You use a short length of rope to tie a rope around the 'equator' of a basketball, more rope to circle a hot air balloon, and a lot of rope to circle the Earth.
When you tell him you finished, he thinks about it and says the rope is too snug against the sphere and that he was wanting the rope to be about a foot off the surface all the way around each of the 3 spheres. He points to little poles you can use to lift the rope off the surface, and goes to the 'rope room' to get you an extension. He comes back with around 6 ft of rope, and says he'll be back later with rope to extend the other two. Which sphere do you go to with the 6 ft of rope to extend the loop?
 

EricNau

Moderator emeritus
Apr 27, 2005
10,728
281
San Francisco, CA
Dude, I just posted an answer above...Look Up! :D

Am I right or close?
Sorry 'bout that.

Yes, 100, 1001 are indeed the next two (and only two) numbers left in the sequence. Congratulations. :)

Each number in the sequence is "nine" represented in a different number systems starting with base-10 and ending with ternary and binary.
 

swiftaw

macrumors 603
Jan 31, 2005
6,328
25
Omaha, NE, USA
A man hires you to tie a rope loop around the equator of spheres as an art project. You use a short length of rope to tie a rope around the 'equator' of a basketball, more rope to circle a hot air balloon, and a lot of rope to circle the Earth.
When you tell him you finished, he thinks about it and says the rope is too snug against the sphere and that he was wanting the rope to be about a foot off the surface all the way around each of the 3 spheres. He points to little poles you can use to lift the rope off the surface, and goes to the 'rope room' to get you an extension. He comes back with around 6 ft of rope, and says he'll be back later with rope to extend the other two. Which sphere do you go to with the 6 ft of rope to extend the loop?

Any of them

The length of the original rope is 2*pi*r. where r is the radius of the sphere
The length of the extended rope needs to be 2*pi*(r+1).

So the difference = 2*pi*(r+1) = 2*pi*r = 2*pi which is approximately 6 feet it is independent of the radius of the sphere
 

JML42691

macrumors 68020
Oct 24, 2007
2,082
2
There are two known ways to make $1.00 out of 50 coins, what are they? Assuming that we are using American currency: $.01 $.05 $.10 $.25 $.50
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.