Question 918867
let's {{{r}}} be the common ratio

{{{16}}},{{{8}}},{{{4}}}

since {{{8/16 = 4/8 = 1/2}}} the common ratio {{{r=1/2}}}


nth term is 

{{{highlight(a[1]r^(n - 1))}}}...where {{{a}}} is first term and {{{r}}} is ratio


since first term {{{a[1]=16}}} and {{{r=1/2}}}

 {{{a[1]r^(n - 1)=highlight(16(1/2)^(n-1))}}}