Respuesta :

This is a geometric series since it has a common ratio of 1/4

[tex]T_n = 400( \dfrac{1}{4} )^{n-1}[/tex]

When n = 15
[tex]T_{15} = 400( \dfrac{1}{4} )^{15-1}[/tex]

[tex]T_{15} = 400( \dfrac{1}{4^{14}} )[/tex]

[tex]T_{15} = \dfrac{400}{67108864} = \dfrac{25}{4194304}[/tex]