Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

You are not logged in.

## #1 2006-03-07 00:00:41

ganesh
Registered: 2005-06-28
Posts: 24,312

### Number quiz

True or False?

(1) The height of Mount Everest is more than 8 kilometers above sea level.

(2) Iron is about twenty times as heavy as water.

(3) The lowest temperature ever rocorded on earth is less than -100  degrees Centigrade.

(4) The volume of Sun is more than 1,000,000 that of earth.

(5) Light, travelling at 186,000 miles per second,  takes more than four years to reach the earth from the nearest star(other than the sun).

(6) A spaceship would take more than 10 years to reach the sun travelling at 40,000 kilometers per hour.

(7) If the age of man in seconds were expressed in Binary system, 50 or more digits would be required.

(8) There are more atoms in a drop of water than number the human population on earth.

(9) It is not possible to dissolve more than 100 grams of common salt (Sodium Chloride) in a liter of water.

(10) More than half of the population of planet earth live in Asia.

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

## #2 2006-03-07 02:43:45

ashwil
Member
Registered: 2006-02-27
Posts: 121

Offline

## #3 2006-03-07 04:41:54

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

### Re: Number quiz

For 8, you say that it depends on the size of the drop, but doesn't surface tension mean that water drops are all a constant size? Maybe not. I don't know.

Also, for 3, it depends on how you interpret the question. Scientists have managed to create temperatures within millionths of a Kelvin to absolute zero. They then recorded this temperature, obviously.

Why did the vector cross the road?
It wanted to be normal.

Offline

## #4 2006-03-07 04:59:18

ashwil
Member
Registered: 2006-02-27
Posts: 121

### Re: Number quiz

mathsy:

For 8, well, I understand that eskimos have a few dozen words for different kinds of snow. In turn, we in the UK have many terms for rain. Any Englishman can tell you that the drop size of rain can vary from a fine mist to a bucketful!!

For 3, I must defer to your greater wisdom. The question did not make reference to nature, so the mathematican's answer has to consider all recordings of temperature. From my research, that was done at MIT where they achieved one half-billionth of a degree above absolute zero (-273C). Of more interest, perhaps, is grappling with the concept that they couldn't possibly get below -273C, no matter where they were in the universe.

Offline

## #5 2006-03-07 05:03:24

ashwil
Member
Registered: 2006-02-27
Posts: 121

### Re: Number quiz

Of course, Q10 is also in doubt using mathsy's logic. Nowehere did the question refer to human population, so I guess that including other mammals, fish, birds, reptiles and, most of all, insects, would bring Africa and South America way up the ranking.

Offline

## #6 2006-03-07 05:04:23

Ricky
Moderator
Registered: 2005-12-04
Posts: 3,791

### Re: Number quiz

For 8, you say that it depends on the size of the drop, but doesn't surface tension mean that water drops are all a constant size? Maybe not. I don't know.

Drops are of constant size under standard temperature and pressure (or at least temperature, I'm not sure how much pressure would have an effect).

"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

Offline

## #7 2006-03-07 05:10:43

ashwil
Member
Registered: 2006-02-27
Posts: 121

### Re: Number quiz

Q8 Just found this reference:

"A molecule is the smallest part of an existing matter (like water), which can still be called like that. These molecules are very small: One drop of water contains a billion water molecules. Water is a combination of oxygen and hydrogen. In a water molecule there are two hydrogen atoms and one oxygen atom"

So, I guess that the answer is 3 billion (about half of the world's human populaton). Yeah! I was right!!!

I still think the approximate nature of this article gives credence to a variable drop size!

Offline