Chapter 12 Sequences and Series - 12.3 Analyze Geometric Sequences and Series - 12.3 Exercises - Skill Practice - Page 815: 52

$\approx 2059.94$

Here, we have $\sum_{i=1}^{12} 8(3/2)^{i-1}$ We know that $S_{n}=a_1(\dfrac{1-r^{n}}{1-r})$ Common ratio $r=\dfrac{3}{2}$ and $a_1= 8$ Now, $S_{12}=8[\dfrac{1-(3/2)^{12}}{1-(3/2)}]$ Hence, $S_{12}=8 \times [\dfrac{1-(3/2)^{12}}{1-(3/2)}] \approx 2059.94$