Combinations and Permutations
Combinations and Permutations
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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.
Geography is the study of the physical features of the earth and the atmosphere surrounding the earth. Geography caters to the weather, the climate, and the landforms of the earth. Weather stations typically have the following instruments:.
Anemometer for measuring wind speed.
Barometer for measuring atmospheric pressure.
Hygrometer for measuring humidity.
Pyranometer for measuring solar radiation.
Rain gauge for measuring liquid precipitation over a set period of time. .
Thermometer for measuring air and sea surface temperature.
Windsock for measuring general wind speed and wind direction.
Wind vane also called a weather vane or a weathercock: it shows whence the wind is blowing.
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Questions related to Geography Instruments ആകാശത്ത് നിന്ന് സ്റ്റീരിയോസ്കോപ്പിക്ക് ക്യാമ...
Largest Cave : Amarnath (J & K) .
The Biggest River Island : Majuli Bramhaputra river, (Assam).
The Highest Airports : Leh Airport (Ladakh).
The Highest Batttle field and the Longest Glacier : Siachen Glacier.
The Highest Road : Road at Khardungla, (in Leh-Manali Sector).
The Largest Artificial Lake : Govind Sagar ( Bhakhra Nangal.
The Largest Dam : Bhakra Dam, on Sutlej river (Punjab).
The Largest Delta : Sunderbans (W. Bengar).
The Largest Desert : Thar (Rajasthan).
The Largest Fresh Water Lake : Kolleru Lake (Andhra Pradesh).
The Largest Lake : Wular Lake (J & K).
The Largest Museum : Indian Museum, Kolkata.
The Largest Planetarium : Birla Planetorium (Kolkata).
The Largest cave temple : Kailash Temple ( Ellora, Maharastra).
The Largest mosque : Jama Masjid (Delhi.
The Longest Canal : Indira Gandhi Canal or Rajasthan Canal (Ra...
Algeria - Land of Algiers .
Argentina - Silvery Land .
Australia - Southern Land .
Austria - Eastern March .
Bahamas - The Shallows .
Bahrain - The Two Seas .
Belarus - White Russia .
Burkina Faso - Land of Honest Men .
Cameroon - Shrimp River .
Cape Verde - Green Cape .
Colombia - Land of Columbus .
Comoros - Moons .
Costa Rica - Rich Coast .
Dominica - Sunday Island .
Ecuador - Equator .
Eritrea - Land of the Red Sea .
Ethiopia - Land of the Blacks .
Guatemala - Place of Many Trees .
Guyana - Land of Many Waters . LINE_F...
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