Permutation and Combination
- In how many ways, the letters of the word 'BANKING' can be arranged ?
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Total letters = 7, but N has come twice.
So, required number of arrangements = 7 ! / 2 !Correct Option: D
Total letters = 7, but N has come twice.
So, required number of arrangements = 7 ! / 2 !
= [7 x 6 x 5 x 4 x 3 x 2 ! ] / 2 ! = 2520
- In how many ways, the letters of the word 'STRESS' can be arranged ?
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Required number of arrangements = 6 ! / 3 ! [∵ S has come thrice ]
Correct Option: D
Required number of arrangements = 6 ! / 3 ! [∵ S has come thrice ]
= [ 6 x 5 x 4 x 3! ] /3 !
= 120
- In how many ways, the letters of the word 'ARMOUR' can be arranged ?
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Number of arrangements n ! /( p ! q ! r ! )
Total letters = 6, but R has come twice.
So, required number of arrangements
= 6 ! / 2 !Correct Option: E
Number of arrangements n ! /( p ! q ! r ! )
Total letters = 6, but R has come twice.
So, required number of arrangements
= 6 ! / 2 ! = (6 x 5 x 4 x 3 x 2 !) / 2 ! = 360
- In how many different ways, can the letters of the word 'INHALE' be arranged ?
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The word 'INHALE' has 6 distinct letters.
∴ Number of arrangements = n !Correct Option: A
The word 'INHALE' has 6 distinct letters.
∴ Number of arrangements = n ! = 6 !
= 6 x 5 x 4 x 3 x 2 x 1
= 720
- If 56Pr + 6 : 54Pr + 3 = 30800 : 1 then the value of r is ?
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∵ 56Pr + 6 : 54Pr + 3 = 30800 : 1
⇒ 56! / (50 - r)! = (30800 x 54!) / (51-r!)Correct Option: B
∵ 56Pr + 6 : 54Pr + 3 = 30800 : 1
⇒ 56! / (50 - r)! = (30800 x 54!) / (51-r!)
⇒ 56 x 55 = 30800/(51 - r)
⇒ 51 - r = 10
∴ r = 41