Question

This one is to hard for me

Answer 1

TIP

This is a G P Geometric Progression

The first term a is 8

The common ratio is 1/6

in this case the ratio is less than 1

`\begin{gathered} r=\text{ }(t_2)/(t_1)=(t_3)/(t_2) \\ r=\text{ }(3)/(18)=(1)/(6)\text{ } \\ S=(a(1-r^(n)))/(1-r)\text{ where r<1} \\ \text{where a=8 , r=}(1)/(6)\text{ and n=8} \\ S_8=(8(1-((1)/(6))^8))/(1-(1)/(6)) \\ S_8=(8(0.9999))/(0.8333) \\ S_8=(79999)/(0.8333) \\ S_8=9.60037\approx10\text{ nearest interger} \end{gathered}`