Question

Find the sum to infinity of the geometric progression 1/3, -2/9, 4/27,.....

• A. 1/3
• B. 1/2
• C. 1/5
• D. 1/4

Answer 1

Answer:

C. 1/5

$r=\frac{-2/9}{1/3}=-2/3$

$\frac{a}{1-r}=\frac{1/3}{1+2/3}=\frac{1/3}{5/3}=1/5$