# How many combinations of 5 items are there?

120

## How do you solve permutations without repetition?

The formula to calculate all permutations without repetitions of the set {1,2,3} is n! (n−r)!

22.2 hours

## How many possibilities are there for a 6 digit password?

“In eleven hours, 100 number combinations can be tested,” said Markert. As attackers can try more Android PINs, a blacklist would make more sense on Android devices….Why six digit PINs are no better for security than four digits.

Four digit Six digit
1234 123456
0000 654321
2580 111111
1111 000000

## What is a 6 digit PIN code?

The Postal Index Number (PIN) or PIN Code is a 6 digit code of Post Office numbering used by India Post. The PIN was introduced on August 15, 1972. There are 9 PIN regions in the country. The first 8 are geographical regions and the digit 9 is reserved for the Army Postal Service.

## How do you find the most repeated word in a string?

Program:

3. import java. util. ArrayList;
4. public class MostRepeatedWord {
5. public static void main(String[] args) throws Exception {
6. String line, word = “”;
7. int count = 0, maxCount = 0;
8. ArrayList<String> words = new ArrayList<String>();

## How many 4 letter combinations are there?

Why Limit The Combinations To Only 7?

Characters Combinations
4 24
5 120
6 720
7 5,040

## How did all my passwords get compromised?

Most security breaches are the result of one thing: sloppy password practices. Too many people make the mistake of choosing weak passwords, or reusing passwords that they have used elsewhere on the internet – making life too easy for malicious hackers trying to gain unauthorised access.

## What is the most strongest password?

• Has 12 Characters, Minimum: You need to choose a password that’s long enough.
• Includes Numbers, Symbols, Capital Letters, and Lower-Case Letters: Use a mix of different types of characters to make the password harder to crack.

## What is a good 4 digit password?

Researchers at the data analysis firm Data Genetics have found that the three most popular combinations—“1234,” “1111,” and “0000”—account for close to 20 percent of all four-digit passwords.

## How long would it take to crack a 4 digit code?

As such, each PIN entry takes approximately 40 seconds, meaning that it would take up to ~111 hours to bruteforce a 4 digit PIN.

## How do you find repetition?

In general, repetitions are taken care of by dividing the permutation by the factorial of the number of objects that are identical. If you look at the word TOOTH, there are 2 O’s in the word. Both O’s are identical, and it does not matter in which order we write these 2 O’s, since they are the same.

64

## How do I count duplicate words in a string in Java?

ALGORITHM

1. STEP 1: START.
2. STEP 2: DEFINE String string = “Big black bug bit a big black dog on his big black nose”
3. STEP 3: DEFINE count.
4. STEP 4: CONVERT string into lower-case.
5. STEP 5: INITIALIZE words[] to SPLIT the string.
6. STEP 6: PRINT “Duplicate words in a given string:”
7. STEP 7: SET i=0.
8. STEP 8: SET count =1.

## How many permutations of 4 are there?

Therefore, there are 4· 3 or 12 possible ways to choose two letters from four. ab means that a was chosen first and b second; ba means that b was chosen first and a second; and so on. Thus the number of permutations of 4 different things taken 4 at a time is 4!.

## How many permutations are there for 6 numbers?

720 different permutations

## Is there repetition in combination?

Any selection of r objects from A, where each object can be selected more than once, is called a combination of n objects taken r at a time with repetition. Two combinations with repetition are considered identical if they have the same elements repeated the same number of times, regardless of their order.

## How do I find repetitive words in Word?

Word: Find duplicated words

1. Press Ctrl+H to open the Find and Replace dialog box.
2. Click More, then select the Use wildcards option.
3. In the Find field, type: (<[A-Za-z]@)[ ,.;:]@\1> (Note: There’s a space in there, so I suggest you copy this Find string.)
4. In the Replace field, type: \1.
5. Click Find Next then click Replace. Repeat.

27

## Can John the Ripper crack any password?

John the Ripper (also called simply ‘John’ ) is the most well known free password cracking tool that owes its success to its user-friendly command-line interface. John has autodetect capability, which often works fine, but in some cases, it might be necessary to guess the hash type.

## What is combination without repetition?

The combinations without repetition of elements taken in are the different groups of elements that can be formed by these elements, so that two groups differ only if they have different elements (that is to say, the order does not matter).