Post me your hardest maths question you know

Okay, this one is a mind****

3 friends go to a restaurant.

They spend a total of 25 pounds, but only have 10 pounds each on them. They pay the waitress, who, being a crafty one, takes 2 pounds in tips. so she gives each of them one pound as change.

Therefore they each spend 9 pounds, as 10-1 = 9.

However (9x3) -[the amount they each spent]- +2 -[the amount the waitress took in tips]- = 29.

So, where did that last pound go?

Mhm :D

Well clearly she's short changed them even more than she said she did the crafty bint. :p
 
Okay, this one is a mind****

3 friends go to a restaurant.

They spend a total of 25 pounds, but only have 10 pounds each on them. They pay the waitress, who, being a crafty one, takes 2 pounds in tips. so she gives each of them one pound as change.

Therefore they each spend 9 pounds, as 10-1 = 9.

However (9x3) -[the amount they each spent]- +2 -[the amount the waitress took in tips]- = 29.

So, where did that last pound go?

Mhm :D

9x3 is the amount they spent including the tip

Bill = £25 - Tip = £2 - Change = £3

Totals £30
 
9x3 is the amount they spent including the tip

Bill = £25 - Tip = £2 - Change = £3

Totals £30

:mad:

Edit: And no I'm not bad at maths, it was my mates problem, we've had a few, I was MIND******, and decided to post it :)

Even though I do a degree in maths, I can still be outfoxed by drunken logic ;)
 
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0.9 recurring equals 1. end of

indeed - anyone who thinks otherwise doesn't correctly understand the concept of infinity.

yousuck.png
 
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Well said dl8860 and Aod! I can't believe people still don't get this... :confused: It's one of the simplest mathematical proofs you can get people! :p
 
indeed - anyone who thinks otherwise doesn't correctly understand the concept of infinity.

yousuck.png

The thing thats possibly wrong with this equation is the assumption the equation makes i.e 1/3 = 0.3r is assuming that you are giving the example of "1/3 of 1" therfore the answer ofcourse will be 1 that the whole point. if you just said 1/3 it could mean anything. when you put 1 / 3 in a calc as i stated earlier due to the infinite number of bits it would need to store it simply rounds it up, in truth 1 / 3 cannot be computed, the equation cannot be finished. so mathematicians got lazy and said lets just round it. :) but i refuse to beleive the answer is 1 :)


i could say well 1 / 3 = 0.3 r
and 2 / 3 = 0.6r

and 3 X 0.3r = 0.9r

therefore 0.9r = 0.9r

and not 1 you cant just add that 0.x1
 
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Greater minds than anyone posting on this board have debated back and forth over this 0.9r=1 concept and never reached an agreed conclusion, it's not something that's going to be miraculously solved by an argument over whether 0.9r multiplied by 10 is 9 or 9.9r.

wrong, very few mathematicians ever argue this, only Internet trolls and an high school students.
 
How about this one -

You travel to america at 100km/h. You then travel back at a constant speed. The average speed for the entire journey is 50km/h. What was your speed in returning from america?

heh heh heh
arent i funny

If I travel in reverse would that count as -X kilometres/hour? I could solve it that way!
 
The thing thats possibly wrong with this equation is the assumption the equation makes i.e 1/3 = 0.3r is assuming that you are giving the example of "1/3 of 1" therfore the answer ofcourse will be 1 that the whole point. if you just said 1/3 it could mean anything.

What? 1/3 is the mathematical representation of "one divided by three". Where do you get the idea of 1/3 "assuming" anything?
 
i could say well 1 / 3 = 0.3 r (1)
and 2 / 3 = 0.6r

and 3 X 0.3r = 0.9r (2)

therefore 0.9r = 0.9r

and not 1 you cant just add that 0.x1

using what you have written:

(2): 3 X 0.3r = 0.9r.

subst (1) into (2): 3 X (1/3) = 0.9r
but 3 X (1/3) = 1 therefore
1 = 0.9r.

oh, thy double edged sword! How thy hath slane one.
 
wrong, very few mathematicians ever argue this, only Internet trolls and an high school students.

First time I've been in this debate but using an old mans wisdom, if I was asked to travel 1 mile until I hit a wall but I only ever went 0.9999r mile then I will never hit the wall.
I have never gone 1 mile therefore 0.9999r can't equal 1
 
First time I've been in this debate but using an old mans wisdom, if I was asked to travel 1 mile until I hit a wall but I only ever went 0.9999r mile then I will never hit the wall.
I have never gone 1 mile therefore 0.9999r can't equal 1

If you "only ever went 0.9r miles" when you would have travelled 1 mile and hit the wall. They are mathematically equivalent, whether your intuition agrees or not.
 
First time I've been in this debate but using an old mans wisdom, if I was asked to travel 1 mile until I hit a wall but I only ever went 0.9999r mile then I will never hit the wall.
I have never gone 1 mile therefore 0.9999r can't equal 1

If two real numbers are different, then you can always find a third number that sits between them.

What number sits between 0.9r and 1?
 
First time I've been in this debate but using an old mans wisdom, if I was asked to travel 1 mile until I hit a wall but I only ever went 0.9999r mile then I will never hit the wall.
I have never gone 1 mile therefore 0.9999r can't equal 1

wrong, you will hit the wall after n infinite time.

You just aren't understanding the concept of infinity.


You also seem to have believe that 0.9r is a different entity to 1.

0.9r means exactly the same thing as 1, it is just 2 different symbols that mean the exact same thing.
By definition, 0.9r = 1. This is absolute true in every sense of the meaning.

What you are arguing is 1 != 1. Which is just absurd.

1=1
1= 0.9r


0.9r does not mean 0.999999999999999999999999999999999999999999999999999.... with a very long repetition of 9s. 0.9r means 1.

Here is another example:
X = 1
Y = 1
X = Y. You are trying to argue that this doesn't hold, of course it holds, by the very definition. X and Y are just different symbols to represent the same thing.
Just because a number has two different symbolic representation doesn't mean they are different.


Its like giving someone a nickname, when you use their full name or their nickname you still refer to the same person, not two different people.
 
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