Answer:
[tex]\boxed{a_{n} = 250(0.4)^{n - 1}}\\[/tex]
Step-by-step explanation:
Step 1. Calculate the common ratio
a₁ = 250
a₂ = 100
a₃ = 40
a₄ = 16
The common ratio is
a₃/a₂ = 40/100 = 0.4
Step 2. Write the formula for the series
The formula for the nth term of a geometric sequence is
aₙ = a₁rⁿ⁻¹
Thus, the formula for the series is
[tex]\boxed{a_{n} = 250(0.4)^{n - 1}}\\[/tex]
