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Math Tricks/Problems
19:47:43 Oct 15th 07 - Mr. Dragonfly:

damn it i give up nvmd.


20:04:53 Oct 15th 07 - Mr. Dragonfly:

why dot you show us sun :D


20:29:39 Oct 15th 07 - Sir Verll:

Cause it's pretty O_o


21:35:58 Oct 15th 07 - Mr. Sigheart:

Consider if the ball is partially submerged and when it is totally submerged.

If it is partially submerged, 
L\0leq{h}<10

If it is totally submerged, 
L\10leq{h}<15

The radius of the bowl is 15 cm and the ball has radius 5 so points on the sections satisfy the equations:

L\x^{2}+y^{2}=225

and

L\x^{2}+(y+10)^{2}=25

Find for the two separate cases.

For L\0leq{h}<10:

L\V={pi}int_{-15}^{h-15}left[(225-y^{2})-(25-(y+10)^{2})
ight]dy

For L\10leq{h}<15

L\V={pi}int_{-15}^{-10}left[(225-y^{2})-(25-(y+10)^{2})
ight]dy+{pi}int_{-10}^{h-15}(225-y^{2})dy


22:19:47 Oct 15th 07 - Mr. Sun:

think you forgot some sqrt.


17:15:20 Nov 6th 07 - Mr. Binh:

Here's some new questions that don't require high level of math:

1. Using number from 0-9, each number must be used once. Fill in the blank so that this is true: _*_+_+_+_+_+_+_+_+_ = 100.

(Record the process that you go about to solve this problem. This mean there shouldn't be any random guessing.)

2. Why is the giant hand only 11 inches long?

(This is more of a joke)

3. Show me how you can use three 8s to create a 7.


17:29:09 Nov 6th 07 - Mr. Lenard:

1. 8*9+0+1+2+3+4+5+6+7 = 100

randomly guessed...can see the adding total is small so most of the 100 has to come from the _*_ bit

2. 12 inches would be a foot

3. -(8/8)+8 ?


17:56:30 Nov 6th 07 - Mr. Revenge:

smart lmao


18:03:29 Nov 6th 07 - Mr. Revenge:

During a recent police investigation, Chief Inspector Stone was interviewing five local villains to try and identify who stole Mrs Archer's cake from the mid-summers fayre. Below is a summary of their statements:

Arnold:  it wasn't Edward
             it was Brian

Brian:   it wasn't Charlie
            it wasn't Edward

Charlie: it was Edward
            it wasn't Arnold

Derek:   it was Charlie
             it was Brian

Edward:  it was Derek
               it wasn't Arnold

It was well known that each suspect told exactly one lie. Can you determine who stole the cake?


18:15:41 Nov 6th 07 - Mr. Binh:

Correct Lenard.

Although for number 1: You can solve it this way:

X*Y+_+_+_+_+_+_+_+_ = 100

I would like to solve for the first two number using X and Y. The remaining is all the numbers that is not X and Y. We know that all the number added together = 45.

From the above information you can get this: 45 - (X+Y) + (X*Y) = 100.
XY-(X+Y) = 100-45 = 55.

From what I got above, we now know that XY > 55. Now all we need to do is find all pairs of number that satisfy XY > 55.

3 pair exists that match this condition: (7,8), (7,9), (8,9).

Now we must find which one of these three pair match the condition XY - (X+Y) = 55. And (8,9) work perfectly :)


18:27:28 Nov 6th 07 - Mr. Binh:

From Brian we know that either Charlie or Edward is the thief since he said exactly 1 lie. From Derek, we know that either Charlie or Brian was the thief since he said 1 truth.

(Charlie or Edward) and (Charlie or Brian) = Charlie.

Charlie is therefore the thief.


18:43:28 Nov 6th 07 - Mr. Revenge:

Once upon a time, and old lady went to sell her vast quantity of eggs at the local market.

When asked how many she had, she replied:

Son, I can't count past 100 but I know that.

If you divide the number of eggs by 2 there will be one egg left.
If you divide the number of eggs by 3 there will be one egg left.
If you divide the number of eggs by 4 there will be one egg left.
If you divide the number of eggs by 5 there will be one egg left.
If you divide the number of eggs by 6 there will be one egg left.
If you divide the number of eggs by 7 there will be one egg left.
If you divide the number of eggs by 8 there will be one egg left.
If you divide the number of eggs by 9 there will be one egg left.
If you divide the number of eggs by 10 there will be one egg left.

Finally. If you divide the Number of eggs by 11 there will be NO EGGS left!

How many eggs did the old lady have?

Well done for the above :)


18:55:48 Nov 6th 07 - Mr. Binh:

10!+1 = 3628801
3628801/11 = 329891 with 0 remainder.

Therefore 3628801 eggs is the answer.


19:08:02 Nov 6th 07 - Mr. Revenge:

no its not lmao


19:27:57 Nov 6th 07 - Mr. Dragonfly:


11* (10! +1)  is an awnser ??

or the old lady is dement


19:52:53 Nov 6th 07 - Mr. Binh:

no my answer is right, but it seem Revenge want to get the smallest number of eggs that satisfy the 10 conditions. To do this you have to go a bit deeper into the math.

Basically to satisfy conditions 1 to 9 it must be divisible by numbers 2 to 10 evenly and add 1 to it. To find the smallest number that satisfy this, you can simply take 2*2*2*3*3*5*7 = 2520. Notice that all number from 2 to 10 can be gotten by multiplying some of the numbers in the set of numbers (2,2,2,3,3,5,7).

We now know that any number times 2520 is all evenly divided by number 2 to 10. Now we need to find a smallest X that satisfy: (2520*X+1) divided 11 evenly. Notice that 2520/11 has a remainder of 1. 2520*2/11 has remainder of 2. 2520*10/11 has remainder of 10. If we add 1 to this, 11 will be evenly divided.

So the smallest number of eggs the lady have is 2520*10+1 = 25,201 eggs.


20:32:37 Nov 6th 07 - Mr. Revenge:

well done ;)


08:00:53 Nov 7th 07 - Mr. Ridukuluz:

can we close this thread?  Its making Binh orgasmic.


15:18:40 Nov 7th 07 - Lord Carnage:

25201
52921
80641
108361
136081
163801
191521
219241
246961
274681
302401
330121
357841
385561
413281
441001
468721
496441
524161
551881
579601
607321
635041
662761
690481
718201
745921
773641
801361
829081
856801
884521
912241
939961
967681
995401

All these numbers(under 1mil) work for your question Mr. Revenge ^^

took me 2mins to write a bruteforce java program for it :D


15:21:10 Nov 7th 07 - Mr. Sun:

Claps for binh!


15:30:16 Nov 7th 07 - Mr. Revenge:

lmao i found the ones i have said in magazines i will give you a new one in a second


15:31:26 Nov 7th 07 - Mr. Revenge:

What number comes next in this sequence:

1/1 3/2 7/5 17/12 41/29 ==?==


15:40:27 Nov 7th 07 - Mr. Sun:

99/70


15:41:11 Nov 7th 07 - Ms. Gene Atalia:

99/70


15:41:51 Nov 7th 07 - Mr. Revenge:

why?


15:51:53 Nov 7th 07 - Ms. Gene Atalia:

The series you wrote are rational approximations of the continued fraction for sqrt(2). The next one in the series is 99/70 and the one after is 239/169.


16:04:45 Nov 7th 07 - Mr. Revenge:

Assume that penguins live with a density of 1,000 penguins per square mile and can run at an average speed of 7 miles per hour on land and swim at 20 miles per hour. Also assume that a polar bear has a territory of 10 square miles, can run at 25 miles per hour and swim at 10 miles per hour, how many penguins will an average polar bear eat in any given month, remembering that a polar bear could, as a maximum, only eat one penguin per hour and 7% of the land is next to the sea.


16:43:46 Nov 7th 07 - Mr. Sun:

The bear drowns after chasing a penguin in the sea for 1 hr and eats 0 penguins.


16:49:55 Nov 7th 07 - Mr. Revenge:

be serious


17:13:45 Nov 7th 07 - Mr. Sun:

Do I count that as a "probable" event? Sometimes math questions neglect reality and make unnatural assumptions. For example, should we assume the penguins are evenly distributed in the bear's territory, or they are all together at the land next to the sea making it easier for all of them to escape into the water - the latter is closer to reality.


17:49:52 Nov 7th 07 - Ms. Gene Atalia:

This isn't a math problem. The answer is none, polar bears live at the north pole while penguins live at the south pole.


17:53:28 Nov 7th 07 - Mr. Revenge:

where do you find these answers......


17:55:56 Nov 7th 07 - Mr. Binh:

haha lol


22:17:04 Nov 7th 07 - Mr. Atreides:

What the heck is sqrt(2)? I thought the answer was that to find the next number, you just double the last number and add the one before it (you do it separately for the numerator and denominator).

As for the other problem, IIII llliiiikkkkkkkeeeeeee ppppeeeennnngggguuuuiiinnnss!


22:22:58 Nov 7th 07 - Ms. Gene Atalia:

"What the heck is sqrt(2)? I thought the answer was that to find the next number, you just double the last number and add the one before it (you do it separately for the numerator and denominator)."

True, but that isn't the complete answer. sqrt(2) means square root of 2.


03:46:47 Nov 8th 07 - Mr. Architect:

Carnage members may NOT answer as they already have the answer in the forums:

You have 2 coins that add up to $.30 and one of them isn't a nickle, what 2 coins do you have?


04:24:53 Nov 8th 07 - Mr. Wizardus:

One isn't a nickel, but the other one can still be a nickel, so it's a quarter and a nickel.


04:40:33 Nov 8th 07 - Sovereign Everyday Combat:

The one that isn't a nickel is a quarter, then the other coin is a nickel =)

Edit- I lost =(


10:16:03 Nov 8th 07 - Lord Seloc:

Umm whats a nickel worth?? 0.o

Find x :

a) (x+4)=0/(5x -10) ----->(Yes I know you can't divide 0 by anything, just assume you can.)
b) (7x+98)^2=0


12:38:49 Nov 8th 07 - Ms. Gene Atalia:

"a) (x+4)=0/(5x -10) ----->(Yes I know you can't divide 0 by anything, just assume you can.)"

Actually you can divide 0 by almost anything, it's just 0. As for x, it's -4.

"b) (7x+98)^2=0"

x = -14.


13:40:44 Nov 8th 07 - Lord Seloc:

lol I made them too easy, try:

c) (8x+32)(2x+20)=0
d) 2x(3+6x)=0


15:57:17 Nov 8th 07 - Lord Software Bug:

c) 8x+32 = 0 or 2x+20=0
8x = -32 or 2x = -20
x = -4 or x = -10

d) 2x = 0 or 3+6x=0
x = 0 or 6x = -3
x = 0 or x = -1/2

Those were indeed simple.


16:12:37 Nov 8th 07 - Mr. Big:

How many digits are in 320748560508296180156178931657902873993848117762051978


16:13:57 Nov 8th 07 - Mr. Big:

massive number, really no math I just like this online calculator I have to use
2.141026x101.7x1028

thats the answer


16:17:01 Nov 8th 07 - Lord Software Bug:

Heres one I like:

Find a 10-digit number with the following properties:

The digits 0-9 only appear once in the number.
The number formed by the first digit (from the left) is divisible by 1. (ie. You get a natural number)
The number formed by the first two digits is divisible by 2.
The number formed by the first three digits is divisible by 3.
The number formed by the first four digits is divisible by 4.
The number formed by the first five digits is divisible by 5.
The number formed by the first six digits is divisible by 6.
The number formed by the first seven digits is divisible by 7.
The number formed by the first eight digits is divisible by 8.
The number formed by the first nine digits is divisible by 9.
The whole number is divisible by 10.


16:29:02 Nov 8th 07 - Mr. Big:

3816547290 ??

all you know at first is that #5 is a 5 and 10 is 0 and that the odd digits are in their respective odd positions 3 7 9

good problem :)


16:34:04 Nov 8th 07 - Lord Software Bug:

Yup. That one seems to work and looks awfully like the number I got when I did the problem (Forgot the exact number, but was probably the same then :P)


16:35:47 Nov 8th 07 - Mr. Big:

#1
Find a 10 digit number such that:
-the first digit tells how many zeros are in the number
-the second digit tells how many ones are in the number
-the third digit tells how many twos are in the number, and so on...
#2
Find the smallest 10 digit number, which uses all the digits (0-9), and is divisible by 1 through 10

just to stay on the 10 digit track :P


18:12:07 Nov 8th 07 - Ms. Gene Atalia:



18:38:04 Nov 8th 07 - Mr. Binh:

1. 9,000,000,000


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