Question

2. If n ! + (n - 1) ! =30, then find the value of n.
3. In how many ways can the letters of the word BANANA be arranged so that all A s
are together

Answer 1

Answer:

Step-by-step explanation:

n ! + (n - 1) ! =30

n (n-1)! + (n-1)! = 30

(n+1)(n-1)! = 30

(n+1)! / n = 30

1/n = 30/(n+1)!

1 = 30n / (n+1)!

1 = 30(n+1)! / (n+1)(n+1)!

1 = 30/(n+1)

n+1=30

n = 30-1

n = 29

(I think the question is wrong.)

May i suppose the question be  n! ÷ (n-1)! = 30

if so,

n! = 30 (n-1)!

(n-1)! n = 30 (n-1)!

=> n = 30