Answer:
The 7th number in the sequence is [tex]\frac{125}{8}[/tex]
Step-by-step explanation:
Geometric sequence:
In a geometric sequence, the quotient between consecutive terms is always the same, called common ratio.
The nth term of a geometric sequence is given by:
[tex]A_n = A(0)r^{n-1}[/tex]
In which A(0) is the first term and r is the common ratio.
1000,-500,250,-125
This means that [tex]A(0) = 1000, r = -\frac{500}{1000} = -\frac{1}{2}[/tex]
So
[tex]A_n = A(0)r^{n-1}[/tex]
[tex]A_n = 1000(-\frac{1}{2})^{n-1}[/tex]
What is the 7th number in the sequence?
This is [tex]A_7[/tex]. So
[tex]A_7 = 1000(-\frac{1}{2})^{7-1} = \frac{1000}{64} = \frac{125}{8}[/tex]
The 7th number in the sequence is [tex]\frac{125}{8}[/tex]
