Question

Find the 15th term in the geometric sequence below.

Answer 1

Geo sequence
$a_n=a_1r^{n-1}$
an=nth term
a1=first term
r=common ratio
n=which term

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

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




C is answer