Respuesta :

geo sequence
[tex]a_n=a_1r^{n-1}[/tex]
an=nth term
a1=first term
r=common ratio
n=which term

10/20=1/2
r=1/2
20=a1

[tex]a_{15}=20(1/2)^{15-1}[/tex]=
[tex]a_{15}=20(1/2)^{14}[/tex]=
[tex]a_{15}=20( \frac{1}{16384} )[/tex]=
[tex]a_{15}= \frac{20}{16384} [/tex]=
[tex]a_{15}= \frac{5}{4096} [/tex]




C is answer