# Puzzles / Riddles

2K

Solutions

3K

Contributors

Puzzles and riddles are statements and questions framed such that they require ingenuity and imagination to resolve. Most are mathematical conundrums, but can also include the arcane, trivial or simply funny.

Can anyone figure out my grandson's Year 4 Math homework? (He is 8!)

I've attached a photo of it.

The Easy and Speedy part is fine.

However "Some subtracting" is weird - those middle numbers crossed out are on the original sheet. I can't figure out how they work. The subtractions themselves obviously work if you just ignore the crossed out numbers, and adjust for hundreds, tens and units, but why are the crossed out numbers there in the first place? They must be some sort of working out, but what? I come up with a rule that explains some of them but I can't explain them all.

Then finally there is 12, 13 and 14: "Choose three numbers to create a 3-digit number. Re-arrange the digits and subtract the smaller number from the larger number. Do this three times". This doesn't seem to me very clear. Is this what they are looking for:

Choose three numbers: 1 8 6
Re-arrange the digits and subtract the smaller number from the larger number: 8 - 6 - 1 = 1

Do this three times - just choose three numbers another two times?
Choose three numbers: 3 9 2
rearrange and subtract: 9 - 3 - 2 = 4

Choose three numbers: 3 8 2
rearrange and subtract: 8 - 3 - 2 = 3

But since these follow from 9, 10 and 11 perhaps the three numbers are similar to those? But I don't see how?

Anyway here are the original questions:
0
I have an extension cord broken and I want to repair it.
It is closed with special head screws, which seems are made only to be tightened.
The head does not allow opening with a normal screwdriver.
I have a set of industrial, special screwdrivers, but none of them helps.
I tried to drill the head of the screw with gold type HSS drill bits, under 0.5 up to 2mm, but it is a very hard material and did not help.
The screws are fixed in plastic/aluminum case of the extension cord. They are not glued. They just need to be unscrewed.
So, how shall loose/open these screws?

0
I'd like to come up with some clever tagline or rhyme for having our users reboot on Thursday.  After we push security updates to endpoints, I want the users to reboot, so I'd like a clever tagline.  For example, if I wanted my users to drink more water, I could say something like, "It's Thirsty Thursday, please make sure you drink plenty of water today!"  Or if I wanted my users to attend a meeting on Tuesday, "It's Technology Tuesday, please come to our technology meeting today!"

Can someone come up with a clever idea because "Reboot Thursday" or "Restart Thursday" just doesn't have a good ring to it!
0
What is the next number in the series : 1,2,4,8 ...
0
refresh tropical mango
rise zero orange.
focus kiwi strawberry
-----------------------------------------
Some catchy phrase needs to be in addition to those.
0
I am interested to know, in the year the gold standard was finally abandoned, 1971...

How many dollars were in circulation at the point in time?
0
We have 12 players, and we would like to set up a 6 team round-robin tournament for a few different backyard games. We'd like to play as many different backyard games as possible with these 12 players (6 teams of 2 players), while ensuring that no two players get matched up more than once across the different games.

Looking for a grid of as many of these unique matchups (round robins) as mathematically possible.

Overview:

Players: 1 - 12
Teams of 2
As many combination of 6 teams as mathematically possible while ensuring no two people end up together on a team more than once
0
Hello Fellow Experts!

I work with service dogs, and our family dog is a breeding dog for the program who is about to have her first litter.

I had the Idea of having her litters be named using a theme of Computers/Technology/Video games.

To do this we need to think of three (3) categories with Fifteen (15) names each that collectively fit this theme.

I need your help narrowing down categories, and coming up with more names for the categories we decide to use.

For example, I got the Idea for this by thinking it would be fun to name dogs these names:
• Packet
• Port
• Socket

The program's organizer liked this Idea and said the would love to have a dog named TeraByte.

However, as I think of names they tend to come from all over and I can see multiple ways of categorizing them, and I tend to be picking names from all over as one big list making it hard to split up.

Here are some ways of Categorizing which I was considering:
• Network/Internet Terms
• Communication Software/Services
• Productivity Software
• Computer/Console Hardware
• PC and Video Games
• Technology professions and terms

Lets discuss which of these are good and whether there are others that might be better.

Here are additional names I have thought of, as you can see they could be categorized many ways:
• MegaByte/MegaBit
• FTP
• email
• hashtag
• SQL (Pronounced Sequel) -- I figure we have to put the pronunciation down for anything not obvious to a non-technical person)
• Java
• Powershell
• Sega
• Atari
0
Black friday shopping!  Walmart and Staples has the 3600 on sale.  But there's a 3700.  higher number, I think is better?

But wikipedia says 3700 is only b/n/g (2.4GHz) and came out in October 2016.  the 3600 came out in april 2016 but has 2.4 / 5GHz.

trying to see the differences beyond that.  Can you help?

thanks
0
What is the maximum distance of x in order to limit the slope change to less than .15 degrees?
0
Hi.

It can be no hard for you guys, but my knowledge in cryptography or anything related is near to 0. So, if anyone can help me.

The puzzle is:

⬅ ➡ ↘

QPLFEFY

15, 41, 54, 59, 201, 255, 355

It's a 7 letters word.
0
Down here in NZ students have just recently sat a horrible algebra paper.  It appears that the examination authority didn't tell the teachers that changes were going to occur in the algebra exam so the teachers taught to what previous exams had asked for.  And all hell has broken loose.

So the attached graphic is a question that occurred in the exam.

I can do most of the paper (with a little bit of revision if I dig out the books) but the question above does not make sense to me.

So what do fellow experts make of it?  If anyone wants the full paper I can supply links.
0
Hi,

I am working on below challenge
http://codingbat.com/prob/p183407

Psedo code:
1. create new array of given difference of size
2. loop through given array
3. fill the new array with given array starting from above difference till end
4. return new array as list
I wrote my code as below

``````public List wordsWithoutList(String[] words, int len) {
int count=0;
int origlen=words.length;
int newLen=origlen-len;
String[] arr=new String[newLen];
for(int i=len-1;i<newLen;i++){
arr[i]=words[i];

}
return Arrays.asList(arr);
}
``````

I am not passing all tests
Expected      Run
wordsWithoutList(["a", "bb", "b", "ccc"], 1) → ["bb", "ccc"]      ["a", "bb", "b"]      X
wordsWithoutList(["a", "bb", "b", "ccc"], 3) → ["a", "bb", "b"]      [null]      X
wordsWithoutList(["a", "bb", "b", "ccc"], 4) → ["a", "bb", "b", "ccc"]      []      X
wordsWithoutList(["xx", "yyy", "x", "yy", "z"], 1) → ["xx", "yyy", "yy"]      ["xx", "yyy", "x", "yy"]      X
wordsWithoutList(["xx", "yyy", "x", "yy", "z"], 2) → ["yyy", "x", "z"]      [null, "yyy", "x"]      X

How to improve/modify my design, code and any other alternate approaches. please advise
0
Hi,

I am working on below challenge
http://codingbat.com/prob/p183837

Psedo code:
1. create new array of given n size
2. loop through given array
3. fill the new array with given array
4. return new array
I wrote my code as below

``````public String[] wordsFront(String[] words, int n) {
int count=0;
String[] arr=new String[n];
for(int i=0;i<n;i++){
arr[i]=words[i];

}
return arr;
}
``````

I am passing all tests

How to improve/modify my design, code and any other alternate approaches. please advise
0
I need your help to identify the song below:
https://soundcloud.com/viki2000/excerpt

It sounds so familiar from Youtube, but I cannot remember it.
It may be soundtrack or instrumnetal.
0
I am doing a research for the subject medicine.

Do you have the encounter with this medicine?

Or, just help me to look up medical information.

Thanks!
0
Dear experts,

I have included the Article (section or regulatory requirements) for calculating the CVA. This formula is provided by Basel and has been adopted by the EBA.

I need help in trying to understand the mathematical operation for arriving at the CVA.

While I am aware that that my question is vague. I will appreciate if anyone can start at a high level in providing the following information:
1. What does the formulae achieve by calculating the square root of a portion of the value which is a square of sum of the individual values (A) and the other section being the sum of the squares of the individual values (B).

Thank you
CVA-question.docx
0
I never expected this to be so difficult.

I need a database (in any form) listing the following:

Date
CountryAttacking
CountryAttacked
Location
War
NumberKilled
NumberWounded

I need this in TXT, CSV or Excel or any other format. I do not need web pages if dates that I need to read. But I could consider screen scraping...as a lot resort.

This is a bit of a puzzle ;P

Thanks
0
I miss a word. It is somewhere deep in my mind and I cannot take it out.
I need a brainstorming to help me to take it out and remember it.
To increase the confusion, I am not so sure if I will be able to define it properly.
Here it is:
-      How do you name/call a person/individual who represents a group, having the same characteristics?
-      When you look at that individual, you see trough/in that person all the others. Like a model, a special type. Maybe is a word related with “type”, maybe sounds as genotype, maybe in Latin.
-      Stereotype is too banal, ordinary and has not a nice connotation.
-      Archetype sounds better, but for me seems that involves something ancient or something initial that was first time.
-      I need the word to express a common set of problems and values. I would like to apply this word or expression to describe a family in needs, which in fact is one family out of thousands in the same situations with the same needs and problems and values. The description would be used to designate all the other families using the name of that representative family.
-      What is that word or expression?
Any other suggestion is welcome.
0
I need to look up telephone numbers of people living in the country Switzerland.
Is there a free WHITE PAGES that has this information online?
I tried searching and the results always seemed to be to sites that CHARGED money for this information.

Any ideas of free sites?

Thank you.
0
Hi,
I am working on below challenge
http://codingbat.com/prob/p136594
I tried my code as below
``````public boolean xyzThere(String str) {
int xPos= str.indexOf('x');
int len=str.length();

String sub=str.substring(xPos,len);
if(sub.equals("xyz")){
return true;
}
else{
return false;
}
}
``````
I am getting below result
Expected      Run
xyzThere("abcxyz") → true      true      OK
xyzThere("abc.xyz") → false      true      X
xyzThere("xyz.abc") → true      false      X
xyzThere("abcxy") → false      false      OK
xyzThere("xyz") → true      true      OK
xyzThere("xy") → false      false      OK
xyzThere("x") → false      false      OK
xyzThere("") → false      Exception:java.lang.StringIndexOutOfBoundsException: String index out of range: -1 (line number:5)      X
xyzThere("abc.xyzxyz") → true      false      X
xyzThere("abc.xxyz") → true      false      X
xyzThere(".xyz") → false      true      X
xyzThere("12.xyz") → false      true      X
xyzThere("12xyz") → true      true      OK
xyzThere("1.xyz.xyz2.xyz") → false      false      OK
other tests
X

how to  improve my approach, results and design of this challenge. How do i make a graphical venn or flow chart or some other relevant diagram to design it before writing code to decide best strategy?
0
Hi,
I am working on below challenge
http://codingbat.com/prob/p126880
I tried my code as below
``````public boolean endOther(String a, String b) {
int aLen=a.length();
int bLen=b.length();

int diff=aLen-bLen;
int absDiff=Math.abs(diff);

if(a.substring(absDiff)==b||b.substring(absDiff)==a){
return true;
}
else{

return false;
}
}
``````
I am getting below result
Expected      Run
endOther("Hiabc", "abc") → true      false      X
endOther("AbC", "HiaBc") → true      false      X
endOther("abc", "abXabc") → true      false      X
endOther("Hiabc", "abcd") → false      false      OK
endOther("Hiabc", "bc") → true      Exception:java.lang.StringIndexOutOfBoundsException: String index out of range: -1 (line number:8)      X
endOther("Hiabcx", "bc") → false      Exception:java.lang.StringIndexOutOfBoundsException: String index out of range: -2 (line number:8)      X
endOther("abc", "abc") → true      true      OK
endOther("xyz", "12xyz") → true      false      X
endOther("yz", "12xz") → false      false      OK
endOther("Z", "12xz") → true      Exception:java.lang.StringIndexOutOfBoundsException: String index out of range: -2 (line number:8)      X
endOther("12", "12") → true      true      OK
endOther("abcXYZ", "abcDEF") → false      false      OK
endOther("ab", "ab12") → false      false      OK
endOther("ab", "12ab") → true      false      X
other tests
X
Your progress graph for this problem

how to  improve my approach, results and design of this challenge. How do i make a graphical venn or flow chart or some other relevant diagram to design it before writing code to decide best strategy?
0
Hi All,

When our Outlook 2010 users log in they are greeted with a certificate error.

Any idea how I can get rid of it.  I'm comfortable deploying certificates via group policy (if that helps)

Many thanks
D
0
Hi,
I am trying below challenge

http://codingbat.com/prob/p100962

I tried as  below
``````public boolean specialEleven(int n) {

if(Integer.mod((n%11)==0))
return true;

else
return false;

}
``````

I am getting below error

Compile problems:

Error:      if(Integer.mod((n%11)==0))
^^^
The method mod(boolean) is undefined for the type Integer

0
Hi,

I am working on below challenge
http://codingbat.com/prob/p137365

i worote as below
``````public boolean in1To10(int n, boolean outsideMode) {

if(n<=10&&n>=1){

return true;
}

else if(n<=1&&outsideMode==true){

return true;
}

else if(n>=10&&outsideMode==true){

return true;
}

else
return false;
}
``````

i am failig one test as below
Expected      Run
in1To10(5, false) → true      true      OK
in1To10(11, false) → false      false      OK
in1To10(11, true) → true      true      OK
in1To10(10, false) → true      true      OK
in1To10(10, true) → true      true      OK
in1To10(9, false) → true      true      OK
in1To10(9, true) → false      true      X
in1To10(1, false) → true      true      OK
in1To10(1, true) → true      true      OK
in1To10(0, false) → false      false      OK
in1To10(0, true) → true      true      OK
in1To10(-1, false) → false      false      OK
other tests

how to fix that and improve my approach and design of this challenge. How do i make a graphical venn or ascii diagram to proceed further. Please advise
0

# Puzzles / Riddles

2K

Solutions

3K

Contributors

Puzzles and riddles are statements and questions framed such that they require ingenuity and imagination to resolve. Most are mathematical conundrums, but can also include the arcane, trivial or simply funny.

Top Experts In
Puzzles / Riddles
Monthly