Brain teasers

I wonder who's a smart guy, i.e, who has a high as IQ

Try and figure this out using soley on algebra

A two digit number has its tens digit five more than two times the units (ones) digit. The number is one less than nine times the sum of its digits. What is the number?

Can't do trial and error cause that's cheap, u must show working in an algerbraric way.

A two digit number has its tens digit five more than two times the units (ones) digit. The number is one less than nine times the sum of its digits. What is the number?

AB
A = (2B)+5
AB = 9(A + B)

Hmmm...I got that far..
I have to go right now, but I'll be back

Let x = the ones
10(2x +5) + x= 9(3x +5) -1
21x +50 = 27x +44
6 = 6x
therefore x =1
therefore units equal one
sub this into original equation
9(3 +5) -1 = 71
therefore the number is 71
pwned

Hmm. I was gunna post a solution, but it involved set theory and I took too long writing <!-- comments.
Anyway.

Wow, wat a smart guy, i jus cant figure out how u got 3x+5 as the sum of the digits

well is he smart or is it the calculator?

Tree Person wrote:

Wow, wat a smart guy, i jus cant figure out how u got 3x+5 as the sum of the digits

Because the tens digit formula was 2x + 5 and the units formula was x
making 3x + 5
and u cant do algebra on a calculator rsguard30 >.<

oh yeah... wat a tough guy... how old r u Hamster?

rsgaurd30 wrote:

well is he smart or is it the calculator?

and that is a funny comment

17
u??

15, i wrote on my profile bit

lol i cbf 2 read
haha but i will anyways
haha im multi-talented like thats

I just realised you both have exactly the same amount of posts: 94.

not anymores
bwayhahahhahahahaha
the 17 year old wins again
bwahahhahahahahha

anyone got anyothers??
lol i wanna c if i can own all of your little brain teasers

The "house" rolls two 20-sided dice and the "player" rolls one 20-sided dice. If the player rolls a number on his dice between the two numbers the house rolled, then the player wins. Otherwise, the house wins (including ties). What are the probabilities of the player winning?

P.S. i like casinos!
(although i am still underaged)

Beat that Hamster!

I calculated that theres 28.5% chance that the player would win.

Am i right, or even close?

Tree Person wrote:

I calculated that theres 28.5% chance that the player would win.

Am i right, or even close?

I think it's right. I have the same number.

here is the answer in full.

It is easily seen that if any two of the three dice agree that the house wins. The probability that this does not happen is 19*18/(20*20). If the three numbers are different, the probability of winning is 1/3. So the chance of winning is 19*18/(20*20*3) = 3*19/200 = 57/200 or 28.5/100.

well done. it took my ages to work it out.

Now this should take awhile.

The winner will recieve 2000 of each resource!

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?

Okay well there r many answers 2 this question
One answer is
25201
another is 3628801
and probably many more

and u posted the answer for the other one be4 i could even come online 2 answer its
>.>

Well the 15year old beat u to it

yep the answer is 25201 and 3628801 and many more.

Tree Person wrote:

Well the 15year old beat u to it

lol only because the 17 year old was out at a concert having the best time of his life

Now the 15 year old is sad

lol haha my bad
*hugs tree person*
u will be able 2 go 2 concerts someday
*gives guitar 2 tree person*
or in one

hey that guitar is made from a protected forest get him!

its alright
it's an electric guitar
forged in the fires of hell
made entirely of recycled paper

Yay, a new guitar, made entirely out of recycled paper....

Anyway, atleast i can get my lisence soon, legal driving age in NZ is 15
That'll make up for not being at that concert

lol your L licence or your actual P licence??

um... we have learners, then restricted, then fulls, i can get my restricted soon

:O
ohhhhhh go tree person
lol im still on my Learners
its 120 hours of driving here now
its taking 4eva!!!!

ya well i jus hope they don't change the driving age before i get my restricted cause they're thinking about it

lol haha just 2 be an ass im gonna put one of my questions on here
so that no one will be able 2 get it

4_ < x - 1
x-2


what are the possible values for x?
lol can anyone actually work it outs?
I wont accept numbers i need 2 c logical progression

i wanna wack a number in but you said i cant . i wish i said that with my other 2.

was there even an algebraic formula for the eggs question?? :S

yeh i think so, cant remeber now, maybe like

x/1=1
x/2=1
etc

bwahahahha no one can even near get an answer 2 mine
and 2 think its an easy one

well im stumped, gimie the answer

4_ < x - 1
x-2

4(x -2) < (x -1)(x -2)^2
4x- 8 < (x-1)(x^2 -4x +4)
4x-8 < x^3-4x^2+4x-x^2+4x-4
0 <x^3-5x^2 + 4x +4
0 < x(x^2 - 5x +4) +4
0 < x(x-4)(x-1) +4
0 < (x+4)(x-4)(x-1)
-4<x<1 or x >4

hehe go my mad maths skills ^^

were you a straight A student who recieved heaps of sholarships?

i wish
thats basic stuff
im like 4th in my maths class :S

I don't get it, i am so lost

on the first line, did u times both sides by x-2 twice???

yeps
it was so that u could know that the value of x-2 was greater than zero
thats y its squared

you lost me on the first 4 and im not even gonna try understanding how you got the final answer.

THAT IS NOT SIMPLE!

Okay, i don't know, i dont no whether that is right, cant be bothered checking, i'll jus say ur too smart....

like i said earlier, is he smart is his teacher/friend/calculator smart?

lol well im super gavin
bwahhahaha
lol does anyone watch friends??