Tips and Ticks Combinations and Permutations


Tips and Ticks Combinations and Permutations

Permutation and combination related questions are common in PSC and Bank exams.

Before going to Combinations and Permutations, first lean about factorial.

If n is a positive integer then, factorial of n is denoted as n!.


5! = ( 1 x 2 x 3 x 4 x 5 ) = 120

4! = (1 x 2 x 3 x 4 ) = 24


Permutations are for lists of items, whose order matters and combinations are for group of items where order doesn’t matter. in other words,

  • When the order of items doesn\\\'t matter, it is called as Combination.
  • When the order of items does matter it is called as Permutation.


The number of permutations of n objects taken r at a time is determined by using this formula:

P(n,r)=n!/(n−r)!

Permutation: Listing your 3 favourite football team in order, from list of 10 teams. P(10,3) = 720.


The number of combinations of n objects taken r at a time is determined by using this formula:

C(n,r)=n!/((n−r)!r!)

Combination: Picking a team of 3 people from a football coaching group of 10. C(10,3) = 10!(3!(10−3)!) = 120.

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Ranks in the Army

കരസേനയിലെ റാങ്കുകൾ.  Code: ജലജ മേജർ ജനറലിനോട് ബിയറിനായി കേണു എൽ സി.ക്ക് മേജറിന്റെ ക്യാപ് ലഭിച്ചു. .


1. ജ : ജനറൽ.

2. ലജ : ലഫ്. ജനറൽ.

3. മേജർ ജനറൽ : മേജർ ജനറൽ.

4. ബിയർ : ബ്രിഗേഡിയർ.

5. കേണു : കേണൽ.

6. L. C : ലഫ്.കേണൽ.

7. മേജർ : മേജർ.

8. ക്യാപ് : ക്യാപ്ടൺ.

9. ലഭിച്ചു : ലഫ്റ്റനന്റ്.

ഇന്ത്യൻ കരസേനയുടെ ഗാനം: മേരാ ഭാരത് മഹാൻ.
ഇന്ത്യൻ സായ...

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BODMAS Rule

BODMAS is an acronym and it stands for Bracket, Of, Division, Multiplication, Addition and Subtraction. .

This explains the order of operations to solve an expression. According to Bodmas rule, if an expression contains brackets ((), {}, []) we have to first solve/simplify the bracket followed by of (powers and roots etc.), then division , multiplication , addition and subtraction from left to right. .

Example :.

7 + (6 × 52 + 3) =   7 + (6 × 25 + 3).

7 + (150 + 3).

7 + (153).

7 + 153 .

Ans: 160. .

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Trick to Remember Mughal Emperors

Code -“BHAJI SABJI FOR MAASAAB”.

B : Babur.

H : Humayun.

A : Akbar.

JI : Jahangir.

S : Shah jahan.

A : Aurangazeb.

B : Bahadur shah.

JI : Jahandar shah.

For : Farrukhsiyar.

M : Muhammad Shah.

A : Ahmad Shah.

A : Alamgir II.

SA : Shah Alam II.

A : Akbar II.

B : Bahadur Shah Zafar.

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