Interesting Math Problems

All the news from the peanut gallery and where all the nasty trash talk fails miserably.
It can get NSFW-ish here: you have been warned!

Moderator: Animal

Post Reply
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#251

Post by Animal »

Yep. The answer is 30.906250.
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#252

Post by Animal »

Let's say there is a basket. And inside the basket are twelve balls. Five of the balls are white. And Seven of the balls are black.

Now, each time you draw out a ball, you note what color it is and then you replace it. As you replace it, you also add back 2 more balls that are the same color. You do this each time you draw out a ball.

What are the odds (your answer must be a fraction or ratio in its lowest denominator) that you drew out a black ball, then drew out another black ball, then drew out a white ball, and then drew out another white ball?
User avatar
QillerDaemon
Crazy Old Cat Lady
Posts: 4019
Joined: Sun Jan 06, 2019 9:35 pm
Location: Beautiful downtown OrloVista FL
Interests: キラーデモン
Occupation: Router/Switch Jockey.

Re: Interesting Math Problems

#253

Post by QillerDaemon »

Animal wrote: Tue Mar 29, 2022 3:51 pm Yep. The answer is 30.906250.
Well, yes you're "right", but this is an olympiad question. They don't want a numerical answer, they want to see you go thru the effort to show a rational form of the right answer. That involves going thru expansions and substitutions to arrive at rational sub-answers, which you'll use for further expansions and substitutions, until you come to the rational answer.

That is to say, besides X2 + Y2 = 2, what else is it equal to? What is X3 + Y3 equal to? What are the patterns as you go up the exponents? Once you arrive at those intermediate formulas, what can you use to simplify them?

The "correct" answer is actually X11 + Y11 = 989/32. You'll come to this once you figure out what X5 + Y5 and X6 + Y6 are equal to.

But geeez, you really want me to go thru all that?! :|
If you can't be a good example, you can still serve as a horrible warning.
“All mushrooms are edible. Some even more than once!”
これを グーグル 翻訳に登録してくれておめでとう、バカ。
User avatar
Bluespruce1964
Tomorrow's Best Poster
Posts: 3925
Joined: Wed Jan 27, 2021 7:04 pm
Location: Oregon
Interests: boating, fishing, dating, travel, music, trivia, crossword puzzles, coffee, reading, photography, swimming, grilling, smoking, building
Occupation: Interloper

Re: Interesting Math Problems

#254

Post by Bluespruce1964 »

4 - 3 + 10 / 5 * 2 =
I'm up early.
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#255

Post by Animal »

Bluespruce1964 wrote: Wed Mar 30, 2022 12:02 pm 4 - 3 + 10 / 5 * 2 =
-3
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#256

Post by Animal »

QillerDaemon wrote: Wed Mar 30, 2022 3:44 am
Animal wrote: Tue Mar 29, 2022 3:51 pm Yep. The answer is 30.906250.
Well, yes you're "right", but this is an olympiad question. They don't want a numerical answer, they want to see you go thru the effort to show a rational form of the right answer. That involves going thru expansions and substitutions to arrive at rational sub-answers, which you'll use for further expansions and substitutions, until you come to the rational answer.

That is to say, besides X2 + Y2 = 2, what else is it equal to? What is X3 + Y3 equal to? What are the patterns as you go up the exponents? Once you arrive at those intermediate formulas, what can you use to simplify them?

The "correct" answer is actually X11 + Y11 = 989/32. You'll come to this once you figure out what X5 + Y5 and X6 + Y6 are equal to.

But geeez, you really want me to go thru all that?! :|
Wow, you never fail to tell me i have the right answer but put a disqualifier on it as though its wrong.

if you want to see the long version, then its 31,648 + (18,272 * sqrt(3)) - 31,648 - (18,272 * squrt(3)) / 2048.

which reduces to (31,648 + 31648)/2048 or 63,296/2048. Now, factoring that down we get 31,648/1024 = 15,824/512 = 7,912/256 = 3956/128 = 1978/64 = 989/32. which is as low as you can go.
User avatar
Bluespruce1964
Tomorrow's Best Poster
Posts: 3925
Joined: Wed Jan 27, 2021 7:04 pm
Location: Oregon
Interests: boating, fishing, dating, travel, music, trivia, crossword puzzles, coffee, reading, photography, swimming, grilling, smoking, building
Occupation: Interloper

Re: Interesting Math Problems

#257

Post by Bluespruce1964 »

Animal wrote: Thu Mar 31, 2022 1:50 pm
Bluespruce1964 wrote: Wed Mar 30, 2022 12:02 pm 4 - 3 + 10 / 5 * 2 =
-3
Isn't is PEMDAS?

4-3+4= 5?

It's been 36 years since I've taken a math class, but I think I still remember how.
I'm up early.
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#258

Post by Animal »

Bluespruce1964 wrote: Thu Mar 31, 2022 11:08 pm
Animal wrote: Thu Mar 31, 2022 1:50 pm
Bluespruce1964 wrote: Wed Mar 30, 2022 12:02 pm 4 - 3 + 10 / 5 * 2 =
-3
Isn't is PEMDAS?

4-3+4= 5?

It's been 36 years since I've taken a math class, but I think I still remember how.
Honestly, I don't know. The way I learned you did Multiply and Divide first in whatever order they came from left to right. Neither Multiply or divide took priority over each other, only how they read left to right. Next Plus and Minus the same way.

The reason I was given at the time was that if there was a reason why you MUST multiply 5*2 before you divide 10/5 then you would use parenthesis to emphasize what goes first. Without parenthesis, you read the equation left to right and solve Multiplication and division first, then add and subtract.

So, this problem becomes 4 - 3 + 2 * 2 = 4 - 3 + 4 = 5. which I got it wrong the first time. I don't know what I did.

Yes, you are right.
Antknot
Not UJR's Military Attaché
Posts: 6741
Joined: Sun Jan 06, 2019 11:30 pm
Location: South Carolina

Re: Interesting Math Problems

#259

Post by Antknot »

Bluespruce1964 wrote: Wed Mar 30, 2022 12:02 pm 4 - 3 + 10 / 5 * 2 =
order of operations is Multiply, divide, add, subtract

so it becomes
4 -{3 + [10 / (5 * 2)}}
4 - {3 +[ 10 / 10]}
4 - { 3 + 1}
4 - 4
0
User avatar
QillerDaemon
Crazy Old Cat Lady
Posts: 4019
Joined: Sun Jan 06, 2019 9:35 pm
Location: Beautiful downtown OrloVista FL
Interests: キラーデモン
Occupation: Router/Switch Jockey.

Re: Interesting Math Problems

#260

Post by QillerDaemon »

Animal wrote: Thu Mar 31, 2022 1:50 pm
Bluespruce1964 wrote: Wed Mar 30, 2022 12:02 pm 4 - 3 + 10 / 5 * 2 =
-3
This is the answer you get if you use C operator precedence. Mult/Div then +/- in left to right order.

Other programming languages will give different answers, since they use a different operator order.
MUMPS (DSM) will give an answer of 4.4, GWBasic will give 0.

That's why there is no answer to this problem. Even mathematicians will disagree on precedence.
If you can't be a good example, you can still serve as a horrible warning.
“All mushrooms are edible. Some even more than once!”
これを グーグル 翻訳に登録してくれておめでとう、バカ。
User avatar
QillerDaemon
Crazy Old Cat Lady
Posts: 4019
Joined: Sun Jan 06, 2019 9:35 pm
Location: Beautiful downtown OrloVista FL
Interests: キラーデモン
Occupation: Router/Switch Jockey.

Re: Interesting Math Problems

#261

Post by QillerDaemon »

Image
If you can't be a good example, you can still serve as a horrible warning.
“All mushrooms are edible. Some even more than once!”
これを グーグル 翻訳に登録してくれておめでとう、バカ。
Antknot
Not UJR's Military Attaché
Posts: 6741
Joined: Sun Jan 06, 2019 11:30 pm
Location: South Carolina

Re: Interesting Math Problems

#262

Post by Antknot »

Image
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#263

Post by Animal »

Hefner's formula was always to divide your own age by 2 and then add 7. No matter what age you are.
User avatar
Bluespruce1964
Tomorrow's Best Poster
Posts: 3925
Joined: Wed Jan 27, 2021 7:04 pm
Location: Oregon
Interests: boating, fishing, dating, travel, music, trivia, crossword puzzles, coffee, reading, photography, swimming, grilling, smoking, building
Occupation: Interloper

Re: Interesting Math Problems

#264

Post by Bluespruce1964 »

If the cost of a bat and a baseball combined is $1.10 and the bat costs $1.00 more than the ball, how much is the ball?
I'm up early.
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#265

Post by Animal »

Bluespruce1964 wrote: Mon Apr 11, 2022 12:42 am If the cost of a bat and a baseball combined is $1.10 and the bat costs $1.00 more than the ball, how much is the ball?
a nickle.
Antknot
Not UJR's Military Attaché
Posts: 6741
Joined: Sun Jan 06, 2019 11:30 pm
Location: South Carolina

Re: Interesting Math Problems

#266

Post by Antknot »

Bluespruce1964 wrote: Mon Apr 11, 2022 12:42 am If the cost of a bat and a baseball combined is $1.10 and the bat costs $1.00 more than the ball, how much is the ball?
..050

Assuming no tax
User avatar
Deathproof
UJR гитара герой чемпион
Posts: 5089
Joined: Sun Jul 14, 2019 3:42 pm
Location: Чикаго, Иллинойс
Interests: музыка, сиськи, литература, сыр и Леттеркенни
Occupation: Я играю на гитаре для жизни

Re: Interesting Math Problems

#267

Post by Deathproof »

What is the next number in this sequence:

3, 13, 1113, 3113, 132113, 1113122113, __________
"Poor kids are just as bright and just as talented as white kids. Wealthy kids, black kids, Asian kids... no I really mean it, but think how we think about it.” -- lifelong segregationist Joe Biden
User avatar
stonedmegman
In Search of vitamin T
Posts: 3445
Joined: Sat Oct 02, 2021 11:41 pm
Location: Looking for Dave

Re: Interesting Math Problems

#268

Post by stonedmegman »

42
QANON IS JUST SCIENTOLOGY FOR HILLBILLIES
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#269

Post by Animal »

311311222113
User avatar
Deathproof
UJR гитара герой чемпион
Posts: 5089
Joined: Sun Jul 14, 2019 3:42 pm
Location: Чикаго, Иллинойс
Interests: музыка, сиськи, литература, сыр и Леттеркенни
Occupation: Я играю на гитаре для жизни

Re: Interesting Math Problems

#270

Post by Deathproof »

Animal wrote: Sun Apr 17, 2022 9:09 pm311311222113
Good job.
"Poor kids are just as bright and just as talented as white kids. Wealthy kids, black kids, Asian kids... no I really mean it, but think how we think about it.” -- lifelong segregationist Joe Biden
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#271

Post by Animal »

Deathproof wrote: Mon Apr 18, 2022 3:46 am
Animal wrote: Sun Apr 17, 2022 9:09 pm311311222113
Good job.
How high would you have to continue this sequence before one of the numbers became a "4"?
User avatar
Deathproof
UJR гитара герой чемпион
Posts: 5089
Joined: Sun Jul 14, 2019 3:42 pm
Location: Чикаго, Иллинойс
Interests: музыка, сиськи, литература, сыр и Леттеркенни
Occupation: Я играю на гитаре для жизни

Re: Interesting Math Problems

#272

Post by Deathproof »

Animal wrote: Mon Apr 18, 2022 4:02 pm
Deathproof wrote: Mon Apr 18, 2022 3:46 am
Animal wrote: Sun Apr 17, 2022 9:09 pm311311222113
Good job.
How high would you have to continue this sequence before one of the numbers became a "4"?
Hmmm... good question. Let's try it out. The next number in the sequence would be 13211321322113. Your turn.
"Poor kids are just as bright and just as talented as white kids. Wealthy kids, black kids, Asian kids... no I really mean it, but think how we think about it.” -- lifelong segregationist Joe Biden
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#273

Post by Animal »

Deathproof wrote: Mon Apr 18, 2022 5:22 pm
Animal wrote: Mon Apr 18, 2022 4:02 pm
Deathproof wrote: Mon Apr 18, 2022 3:46 am
Animal wrote: Sun Apr 17, 2022 9:09 pm311311222113
Good job.
How high would you have to continue this sequence before one of the numbers became a "4"?
Hmmm... good question. Let's try it out. The next number in the sequence would be 13211321322113. Your turn.
1113122113121113222113. your turn.
User avatar
Deathproof
UJR гитара герой чемпион
Posts: 5089
Joined: Sun Jul 14, 2019 3:42 pm
Location: Чикаго, Иллинойс
Interests: музыка, сиськи, литература, сыр и Леттеркенни
Occupation: Я играю на гитаре для жизни

Re: Interesting Math Problems

#274

Post by Deathproof »

Animal wrote: Mon Apr 18, 2022 6:43 pm
Deathproof wrote: Mon Apr 18, 2022 5:22 pm
Animal wrote: Mon Apr 18, 2022 4:02 pm
Deathproof wrote: Mon Apr 18, 2022 3:46 am
Animal wrote: Sun Apr 17, 2022 9:09 pm311311222113
Good job.
How high would you have to continue this sequence before one of the numbers became a "4"?
Hmmm... good question. Let's try it out. The next number in the sequence would be 13211321322113. Your turn.
1113122113121113222113. your turn.
31131122211311123113322113
"Poor kids are just as bright and just as talented as white kids. Wealthy kids, black kids, Asian kids... no I really mean it, but think how we think about it.” -- lifelong segregationist Joe Biden
User avatar
Animal
The Great Pretender
Posts: 28034
Joined: Mon Jan 21, 2019 11:18 pm

Re: Interesting Math Problems

#275

Post by Animal »

Deathproof wrote: Tue Apr 19, 2022 11:40 am
Animal wrote: Mon Apr 18, 2022 6:43 pm
Deathproof wrote: Mon Apr 18, 2022 5:22 pm
Animal wrote: Mon Apr 18, 2022 4:02 pm
Deathproof wrote: Mon Apr 18, 2022 3:46 am
Animal wrote: Sun Apr 17, 2022 9:09 pm311311222113
Good job.
How high would you have to continue this sequence before one of the numbers became a "4"?
Hmmm... good question. Let's try it out. The next number in the sequence would be 13211321322113. Your turn.
1113122113121113222113. your turn.
31131122211311123113322113
132113213221133112132123222113
Post Reply