Combinations and Permutations
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.
കുലീന ലോഹങ്ങള്‍ .
Code: വെള്ളിയാഴ്ച സുവര്‍ണ്ണ ഫ്‌ളാറ്റില്‍ വരും (വെള്ളി, സ്വര്‍ണ്ണം, പ്ലാറ്റിനം).
ദ്രാവകാവസ്ഥയിലുള്ള ലോഹങ്ങള്‍ .
Code: MG ഫ്രാന്‍സിസ്‌ (മെര്‍ക്കുറി, ഗാലിയം, ഫ്രാന്‍സിയം, സീസിയം).
ഭൂമിയില്‍, പ്രപഞ്ചത്തില്‍, അന്തരീക്ഷത്തില്‍ ഏറ്റവും കുടുതലുള്ള മൂലകങ്ങള്‍ .
Code: BO PH AN (B - ഭൂമിയില്‍ O -ഓക്‌സിജന്‍, P - പ്രപഞ്ചത്തില്‍ H -ഹൈഡ്രജന്‍, A - അന്തരീക്ഷത്തില്‍ N -ന...
These are the different type of questions asked from this topic.
Type 1: Find the time when the angle between the two hands are given.
Type 2: Find the angle between the 2 hands when the time is given.
Type 3: Find the time, when clocks gaining/losing time.
Type 4: Find the time in the mirror image.
ക്ലോകിലെ ഓരോ അക്കങ്ങൾക്കിടയിലെ കോണളവ്= 30°.
മിനിറ്റ് സൂചി ഓരോ മിനുറ്റിലും 6° ചുറ്റും.
മണിക്കൂർ സൂചി ഒരു മിനുറ്റിൽ ½°ചുറ്റും.
ഒരുദിവസം Hour, Minute സൂചികൾ 22 തവണ ഒന്നിന് മീതെ ഒന്നായി വരും.
ക്ലോകിലെ സൂ...
Code: MBBS PAIN.
M: Malideep.
B: Bhutan.
B: Bengladesh.
S: Srilanka.
P: Pakistan.
A: Afganistan.
I: India.
N: Nepal.
...
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