Answer:
5
Step-by-step explanation:
The nth term of a geometric series is:
a_n = a₁ (r)^(n-1)
where a₁ is the first term and r is the common ratio.
Here, we have:
40 = a₁ (r)^(4-1)
160 = a₁ (r)^(6-1)
40 = a₁ (r)^3
160 = a₁ (r)^5
If we divide the two equations:
4 = r^2
r = 2
Now substitute into either equation to find a₁:
40 = a₁ (2)^3
40 = 8 a₁
a₁ = 5
