Advertisements
Advertisements
Question
Find n, if `1/("n"!) = 1/(4!) - 4/(5!)`
Advertisements
Solution
`1/("n"!) = 1/(4!) - 4/(5!)`
∴ `1/("n"!) = 1/(4!) - 4/(5!)`
∴ `1/("n"!) = 5/(5xx4!)- 4/(5!)`
∴ `1/("n"!) = 5/(5!)-4/(5!)`
∴ `1/("n"!) = 1/(5!)`
∴ n! = 5!
∴ n = 5
APPEARS IN
RELATED QUESTIONS
A teacher wants to select the class monitor in a class of 30 boys and 20 girls. In how many ways can he select a student if the monitor can be a boy or a girl?
If numbers are formed using digits 2, 3, 4, 5, 6 without repetition, how many of them will exceed 400?
Evaluate: 8! – 6!
Compute: `(9!)/(3! 6!)`
Compute: `(6! - 4!)/(4!)`
Write in terms of factorial:
3 × 6 × 9 × 12 × 15
Write in terms of factorial:
6 × 7 × 8 × 9
Find n, if `"n"/(8!) = 3/(6!) + 1/(4!)`
Find n if: `("n"!)/(3!("n" - 5)!) : ("n"!)/(5!("n" - 7)!)` = 10:3
Find n, if: `((17 - "n")!)/((14 - "n")!)` = 5!
Find n, if: `((15 - "n")!)/((13 - "n")!)` = 12
Show that: `(9!)/(3!6!) + (9!)/(4!5!) = (10!)/(4!6!)`
Find the value of: `(5(26!) + (27!))/(4(27!) - 8(26!)`
Show that: `((2"n")!)/("n"!)` = 2n(2n – 1)(2n – 3)....5.3.1
A hall has 12 lamps and every lamp can be switched on independently. Find the number of ways of illuminating the hall.
A question paper has 6 questions. How many ways does a student have if he wants to solve at least one question?
