Answer
It is not a geometric sequence.
Work Step by Step
A sequence is geometric if $\frac{a_2}{a_1}=\frac{a_3}{a_2}=\frac{a_4}{a_3}=...=r$
For the given sequence we have that:
$\frac{a_2}{a_1}=\frac{\frac{2}{5}}{\frac{1}{4}}=\frac{2}{5}\frac{4}{1}=\frac{8}{5}$
$\frac{a_3}{a_2}=\frac{\frac{3}{6}}{\frac{2}{5}}=\frac{3}{6}\frac{5}{2}=\frac{15}{12}=\frac{5}{4}$
It is not a geometric sequence.
