Hmm... finally one I may be able to figure out. Let me think about it.
Re: Challenging Math Problems (Or not)
Posted: June 19th, 2010, 8:00 pm
by lllazar
blue cobra wrote:
lllazar wrote:Here's one that tripped me up for a few days:
Find the next number in the sequence and the solution
53
You subtract the second digit of the number from the first digit, and then subtract this from the whole number to get the next number in the sequence.
Yes, that is a possible solution and i thought of that too but it wouldn't work for all sequences of this kind. Can you find the other way to do it? Hint: 9.
Re: Challenging Math Problems (Or not)
Posted: June 20th, 2010, 7:38 am
by SOninja
RandomPerson52 wrote: "You are trapped in a prison and the guard decides to play a game. If you win, you will be allowed to leave. But if you lose, you die. The guard says that he is thinking of number 1, number 2, or number 3. You are allowed to ask one question to find out which of these three numbers the guard has in mind. However, the guard will only answer with a “yes”, “no”, or “I don’t know”. What should you say to the guard?"
uhhh :/ i'll venture a guess
"is the number either even or prime?"
Re: Challenging Math Problems (Or not)
Posted: June 20th, 2010, 8:39 am
by winneratlife
SOninja wrote:
RandomPerson52 wrote: "You are trapped in a prison and the guard decides to play a game. If you win, you will be allowed to leave. But if you lose, you die. The guard says that he is thinking of number 1, number 2, or number 3. You are allowed to ask one question to find out which of these three numbers the guard has in mind. However, the guard will only answer with a “yes”, “no”, or “I don’t know”. What should you say to the guard?"
uhhh :/ i'll venture a guess
"is the number either even or prime?"
Won't work, cuz he will only answer "yes" or "no"
The answer to that would have to be like "yes but no"
Re: Challenging Math Problems (Or not)
Posted: June 20th, 2010, 8:43 am
by paleonaps
I think this is it-
"Is the number prime, my dear fellow?"
Re: Challenging Math Problems (Or not)
Posted: June 20th, 2010, 8:55 am
by winneratlife
paleonaps95 wrote:I think this is it-
"Is the number prime, my dear fellow?"
And if he says yes?
Re: Challenging Math Problems (Or not)
Posted: June 20th, 2010, 9:41 am
by RandomPerson
SOninja wrote:
uhhh :/ i'll venture a guess
"is the number either even or prime?"
He can only answer "yes", "no" or "I don't know". You can't ask that question.
There are 3 possible numbers, and 3 possible responses. A correct answer (there are many) will have these three responses differentiate between the three. Getting "Yes" and "No" is easy, its the "I don't know" which becomes difficult.
paleonaps95 wrote:I think this is it-
"Is the number prime, my dear fellow?"
Yes -> 2 or 3
No -> 1
If you get Yes, You can't be sure if it is 2 or 3 and risk getting killed. This is incorrect.
Re: Challenging Math Problems (Or not)
Posted: June 20th, 2010, 9:41 am
by lllazar
winneratlife wrote:
paleonaps95 wrote:I think this is it-
"Is the number prime, my dear fellow?"
And if he says yes?
Ya, wat comes after the yes, if he does say yes. It could be 2 or 3.
Re: Challenging Math Problems (Or not)
Posted: June 20th, 2010, 10:02 am
by paleonaps
You then divide by zero, so that this happens:
Re: Challenging Math Problems (Or not)
Posted: June 20th, 2010, 10:15 am
by winneratlife
RandomPerson52 wrote:
SOninja wrote:
uhhh :/ i'll venture a guess
"is the number either even or prime?"
He can only answer "yes", "no" or "I don't know". You can't ask that question.
There are 3 possible numbers, and 3 possible responses. A correct answer (there are many) will have these three responses differentiate between the three. Getting "Yes" and "No" is easy, its the "I don't know" which becomes difficult
Given that the guard knows all about math, doesn't this make it impossible? That was my first thought.
I'm going to assume that the "I don't know" fits with 1 though...
