Sven's Official BrainTeaser Thread !! and Sander.

[Royal Freakiness]

7+6+3+2+1 = 19, not 14...

those are his number of pies left at that current time

now theres 0 remaining pies for the third guy... who bought 0/2 = 0

the last person also takes .5?

shh u werent meant to notice that part...

 :bang:

lmfao, it looked like you were making sense till the the third guy  :lol:

[Mike]

I'm guessing 17 pies?

x = amount of pies

x=(x/2 + 0.5) + ((x/2 + 0.5)/2 + 0.5) + (((x/2 + 0.5)/2 + 0.5))/2 + 0.5)
         guy 1                 guy 2                              guy 3

which gets to

8x=7x+17
x=17

making the first guy buying 9, second 5 and the last one 3.

Edit: Not correct.

[TW89]

7?

I agree.
7/2=3.5+.5=4 (with 3 remaining)
3/2=1.5+.5=2 (with 1 remaining)
1/2=.5+.5=1 (with 0 remaining)

Macca was on right lines, but last guy needs to take .5, so it must be 7 pies in total.

[a;sdlfkjas;df]

((x/2 + 0.5)/2 + 0.5) + (((x/2 + 0.5)/2 + 0.5))/2 + 0.5)

in here,  shouldn't the total amount of pies left be (x/2-.5)?  then adjusted accordingly here

considering sputnik's explanation, for each multiple of .5 that the customer takes after he takes 1/2 of what is there, the amount of total pies increases by a multiple of 7

if correct:

.5=7
1=14
1.5=21
2=28
...

[Sander]

a;lkjnofihb is right, it's 7  :thumbsup:

first man buys half (3,5) and another half, so he buys four pies in total
second man buys half of the remainder three + another half so he buys 1,5+0,5=2 pies
there's one pie left, the third man buys half of it + another half = that remainder pie

[SvenF]

Ok, I got a new one.

Imagine that there is a rope which lays all around the earth (for example at the equator) on the ground, and it comes to exactly the same place where it started. So in fact the rope is as long as the peryphery of the earth. Now you add 1 meter to the whole rope. Now imagine that you lift the rope all around the earth to the same height. How high can you lift the rope? Note that it has to be the same height at every place.

[Macca]

is there no other information given? like how long the rope was initially? or anything like that?

otherwise i did some research and here is my answer

circumfrence = pi * diameter
initially the circumference is 40,075.16 km (from google)
and the earths diameter is 12,756.32 (from google)
so 40075.16 + 1 = pi * diameter
diameter = 40076.16/pi
= 12756.7928283384... km
this minus earths diameter = 0.317928283384... km
= 318 metres, wtf must be because the numbers i got are rounded off estimations

there must be more to the question...

[Sander]

is there no other information given? like how long the rope was initially? or anything like that?

otherwise i did some research and here is my answer

circumfrence = pi * diameter
initially the circumference is 40,075.16 km (from google)
and the earths diameter is 12,756.32 (from google)
so 40075.16 + 1 = pi * diameter
diameter = 40076.16/pi
= 12756.7928283384... km
this minus earths diameter = 0.317928283384... km
= 318 metres, wtf must be because the numbers i got are rounded off estimations

there must be more to the question...

this is where you make a mistake in your calculations since the circumference of the earth is in kilometres and what must be added is 1 metre, but you added one kilometre

[TW89]

is there no other information given? like how long the rope was initially? or anything like that?

otherwise i did some research and here is my answer

circumfrence = pi * diameter
initially the circumference is 40,075.16 km (from google)
and the earths diameter is 12,756.32 (from google)
so 40075.16 + 1 = pi * diameter
diameter = 40076.16/pi
= 12756.7928283384... km
this minus earths diameter = 0.317928283384... km
= 318 metres, wtf must be because the numbers i got are rounded off estimations

there must be more to the question...

(Could be wrong, but) I think the bit 'bout the earth is irrelevant, like just to use as an example, like sanders and the freestylers, it wasn't really important about them you know. The main bit is how high can you lift it, I think it could be around anything e.g. a circle

Anyway, isn't it like 3.30am over there? lol

[sputnik]

rope is Zmeters long to start

(z+1)= new perimeter.

z= old perimeter

perimeter = pi*diameter

x= diameter new- diameter old= (z+1)/pi - z/pi= (z+1-z)/pi= 1/pi= some number (0.318m i think)

it works for any number you input as z i think

[Macca]

yes its 3.30 am, but ive finished school forever and now i have a reaally long summer holiday =D

time to try TW89's suggestion

lets say its a ball thats 1m in diameter

c = 1 * pi = pi (3.14...)
new c = 1 + pi
new d = (1+pi)/pi
= 1.318
minus 1 = 0.318 metres (31.8cm) above the balls surface

if its a ball with 2m diameter

c = 2 * pi
new c = 1 + (2 * pi)
new d = [1 + (2 * pi)]/pi
= 2.318
minus 2 = 0.318 metres (31.8cm) above the balls surface

yep that sounds right, haha im such an idiot for getting all those values off google
(credit goes to TW89 for this one)

edit: sputnik beat me to it -.-

[SvenF]

rope is Zmeters long to start

(z+1)= new perimeter.

z= old perimeter

perimeter = pi*diameter

x= diameter new- diameter old= (z+1)/pi - z/pi= (z+1-z)/pi= 1/pi= some number (0.318m i think)

it works for any number you input as z i think

Your thinking is almost right. You forget that x= radius new- radius old= (diameter new- diameter old)/2 (because x is on both sides of the earth. so the solution is 0.318/2 =0.159m= 15,9cm
You can try this with a table tennis ball, a football etc. The distance x always stays the same, as you said sputnik it works for any number you input as z. We learned this at school and I thought at the beginning that x would be like some millimeters because the earth is so huge:)