Question

If aₙ = n(a ₙ-₁) and a₁ = 1, what is the value of a₅?

Answer 1

The correct answer is Option c (120).

Explanation:

The given value is:

`a_1=1`

`a_n=n(a_(n-1))`....(equation)

On putting the value of
`a_1` in the above equation, we get

⇒
`a_2=2(a_(2-1))`

`=2(a_1)`

`=2* 1`

`=2`

⇒
`a_3=3(a_(3-1))`

`=3(a_2)`

`=3* 2`

`=6`

⇒
`a_4=4(a_(4-1))`

`=4(a_3)`

`=4* 6`

`=24`

hence,

⇒
`a_5=5(a_(5-1))`

`=5(a_4)`

`=5* 24`

`=120`

Thus the above is the correct solution.