Question

What is the 7th term of the geometric sequence 4, -20, 100, …?

Answer 1

`7` th term is `62500`

Explanation:

`n` th term of geometric sequence is `T_n= a*r^(n-1); a,r,n` are the first term , common ratio and requred term respectively.

Here `a =4 ,r = -20/4=100/-20= -5 , n= 7 :. T_7= 4*(-5)^(7-1)` or

`T_7= 4*(-5)^6=62500` [Ans]