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प्रश्न
In how many ways can 10 examination papers be arranged so that the best and the worst papers never come together?
विकल्प
9 × 8!
8 × 8!
9 × 9!
8 × 9!
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उत्तर
8 × 9!
Explanation:
Arrange 8 papers in 8! ways and two papers in 9 gaps are arranged in 9P2 ways.
Required number = 8! 9P2
= 8! × 9 × 8
= 9! × 8
APPEARS IN
संबंधित प्रश्न
Evaluate: 8!
Evaluate: 10! – 6!
Compute: `(12/6)!`
Compute: (3 × 2)!
Compute: `(9!)/(3! 6!)`
Compute: `(8!)/(6! - 4!)`
Write in terms of factorial.
5 × 6 × 7 × 8 × 9 × 10
Evaluate : `("n"!)/("r"!("n" - "r")!)` for n = 8, r = 6
Evaluate `("n"!)/("r"!("n" - "r")!)` for n = 15, r = 10
Evaluate : `("n"!)/("r"!("n" - "r")!)` for n = 15, r = 8
Find n, if `"n"/(8!) = 3/(6!) + (1!)/(4!)`
Find n, if `"n"/(6!) = 4/(8!) + 3/(6!)`
Find n, if (n + 1)! = 42 × (n – 1)!
Find n, if (n + 3)! = 110 × (n + 1)!
Find n, if: `((17 - "n")!)/((14 - "n")!)` = 5!
Find n, if: `((15 - "n")!)/((13 - "n")!)` = 12
Find n, if: `("n"!)/(3!("n" - 3)!) : ("n"!)/(5!("n" - 5)!)` = 5 : 3
Find n, if: `((2"n")!)/(7!(2"n" - 7)!) : ("n"!)/(4!("n" - 4)!)` = 24 : 1
Show that `("n"!)/("r"!("n" - "r")!) + ("n"!)/(("r" - 1)!("n" - "r" + 1)!) = (("n" + 1)!)/("r"!("n" - "r" + 1)!)`
Show that `((2"n")!)/("n"!)` = 2n (2n – 1)(2n – 3) ... 5.3.1
Simplify `((2"n" + 2)!)/((2"n")!)`
Simplify n[n! + (n – 1)!] + n2(n – 1)! + (n + 1)!
Simplify `("n" + 2)/("n"!) - (3"n" + 1)/(("n" + 1)!)`
Simplify `1/(("n" - 1)!) + (1 - "n")/(("n" + 1)!)`
Simplify `1/("n"!) - 3/(("n" + 1)!) - ("n"^2 - 4)/(("n" + 2)!)`
Simplify `("n"^2 - 9)/(("n" + 3)!) + 6/(("n" + 2)!) - 1/(("n" + 1)!)`
Select the correct answer from the given alternatives.
Find the number of triangles which can be formed by joining the angular points of a polygon of 8 sides as vertices.
Answer the following:
Find the number of words that can be formed by using all the letters in the word REMAIN If these words are written in dictionary order, what will be the 40th word?
Find the number of integers greater than 7,000 that can be formed using the digits 4, 6, 7, 8, and 9, without repetition: ______
If `((11 - "n")!)/((10 - "n")!) = 9,`then n = ______.
Let Tn denote the number of triangles which can be formed using the vertices of a regular polygon of n sides. If Tn + 1 – Tn = 21, then n is equal to ______.
