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Posted: Sun Oct 14, 2007 9:47 am
by akj
@Derek
The hole is drilled from the very top of the sphere to the very bottom of the sphere, passing through the centre of the sphere.
[I have a .JPG image on my HDD that I woulde like to show you, but I don't know how to use the Img tag to add an image to this post]
Posted: Sun Oct 14, 2007 10:06 am
by Derek
You would have to store the image on the net somewhere and then just put the url between some img tags, hover over the img button when posting to see the way to do it.
Anyway, how wide is this hole that is drilled or doesn't it matter?
Posted: Sun Oct 14, 2007 10:15 am
by akj
@Derek
The problem can be solved (producing an answer in cubic metres) without knowing the width/diameter of the hole.
By the way, the answer of 41887.90204786667 posted earlier is incorrect.
Posted: Sun Oct 14, 2007 12:36 pm
by Joakim Christiansen
akj wrote:@Derek
The problem can be solved (producing an answer in cubic metres) without knowing the width/diameter of the hole.
It just doesn't sound right, if you can't know how much mass was drilled out how can you ever figure out what is remaining?
Posted: Sun Oct 14, 2007 2:03 pm
by Derek
So if the diameter of the sphere is 1m and I drilled through it using a drill with a radius of 0.5m or above then I would completely remove the sphere so I'm going to say the answer is 'nothing left'.
Posted: Sun Oct 14, 2007 2:05 pm
by akj
@Joakim,
I know the sphere problem sounds impossible, but if you go carefully through the mathematics/geometry of it, you can reach a perfectly good solution without any tricks or cheating.
The answer is a number [greater than zero] of cubic metres.
Here are some formulae to help you:
The volume of a sphere is PI*r*r*r*4/3
The volume of a spherical cap is PI*h*h*(r-h/3)
The volume of a cylinder is PI*R*R*H
Where:
r is the radius of the sphere
h is the height of the spherical cap (measured perpendicularly from the centre of it's circular base)
R is the radius of the cylinder
H is the height of the cylinder
Posted: Sun Oct 14, 2007 4:18 pm
by Rook Zimbabwe
I was assuming that the hole was 1M long... therefore the radius was 1M and the volume calc followed... I probably should have used a calculator rather than pencil and paper (more fun that way though!)
Posted: Mon Oct 15, 2007 3:49 am
by citystate
akj wrote:@Joakim,
Here are some formulae to help you:
The volume of a sphere is PI*r*r*r*4/3
The volume of a spherical cap is PI*h*h*(r-h/3)
The volume of a cylinder is PI*R*R*H
Where:
r is the radius of the sphere
h is the height of the spherical cap (measured perpendicularly from the centre of it's circular base)
R is the radius of the cylinder
H is the height of the cylinder
I think your question is flawed
the best anyone can do with the information you gave is answer with a formula, not a number. There are too many variables...
oh and the German is the fish-lover
Posted: Mon Oct 15, 2007 3:55 am
by Matt
So, how bout some fun puzzles :roll:
Posted: Mon Oct 15, 2007 2:49 pm
by Irene
Matt wrote:So, how bout some fun puzzles :roll:
Thomas has 20 pearls, but his friend Mike has 43 pearls. Lisa has 70% less pearls than Mike. How many percent does Mike have more pearls than Thomas and Lisa together?
It's fun to solve such easy puzzles ^o^
Posted: Mon Oct 15, 2007 3:14 pm
by Rook Zimbabwe
Please remember that over 80% of statistics are made up on the spot!
That said... I am thinking that lisa has 20 pearls also... (did without involving any of that messy math stuff) so 3 more paerls than both would be .9%
Posted: Mon Oct 15, 2007 6:22 pm
by Irene
Rook Zimbabwe wrote:Please remember that over 80% of statistics are made up on the spot! 8)
That said... I am thinking that lisa has 20 pearls also... (did without involving any of that messy math stuff) so 3 more paerls than both would be .9%
Wrong ^o^
The answer is, Mike has less pearls than Thomas and Lisa together.
Thomas = 20
Mike = 43
Lisa = 43 * 0,7 = 30,1 ~ 30
(20 + 30) > 43.
I knew I would make someone miscalculate even a simple puzzle like that ^_^
Hahaha you're busted Rook! ^o^
Posted: Mon Oct 15, 2007 6:36 pm
by Nik
You distracted him with your appearance that's cheating
Posted: Mon Oct 15, 2007 6:38 pm
by Irene
Nik wrote:You distracted him with your appearance that's cheating :D
^o^
Hallo süßer, tolles Bild! ^_^
Posted: Mon Oct 15, 2007 6:51 pm
by Derek
Irene wrote:Thomas has 20 pearls, but his friend Mike has 43 pearls. Lisa has 70% less pearls than Mike. How many percent does Mike have more pearls than Thomas and Lisa together?
Is it just me or does anyone else read that as Lisa having 70% less than 43 = ~13, for Lisa to have 30 shouldn't it read Lisa has 70% of 43 ?