Advertisements
Advertisements
Question
Evaluate: 8! – 6!
Advertisements
Solution
8! – 6!
= 8 × 7 × 6! – 6!
= 6! (8 × 7 − 1)
= 6! (56 − 1)
= 6! × 55
= 6 × 5 × 4 × 3 × 2 × 1 × 55
= 39,600
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?
How many three-digit numbers can be formed using the digits 2, 3, 4, 5, 6 if digits can be repeated?
If numbers are formed using digits 2, 3, 4, 5, 6 without repetition, how many of them will exceed 400?
Evaluate: 6!
Compute: `(12!)/(6!)`
Compute: `(12/6)!`
Compute: 3! × 2!
Write in terms of factorial:
5 × 6 × 7 × 8 × 9 × 10
Write in terms of factorial:
3 × 6 × 9 × 12 × 15
Write in terms of factorial:
5 × 10 × 15 × 20 × 25
Evaluate: `("n"!)/("r"!("n" - "r"!)` For n = 12, r = 12
Find n, if `1/("n"!) = 1/(4!) - 4/(5!)`
Find n, if (n + 1)! = 42 × (n – 1)!
Find n, if (n + 3)! = 110 × (n + 1)!
Find n if: `("n"!)/(3!("n" - 5)!) : ("n"!)/(5!("n" - 7)!)` = 10:3
Find n, if: `((17 - "n")!)/((14 - "n")!)` = 5!
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
