Answer:
40/3 option B
Step-by-step explanation:
20-10+5-5/2+ ...
We need to find the sum of infinite geometric series
[tex]S_n = \frac{a}{1-r}[/tex]
a is the first term (20)
r is the common ratio
To find common ratio we divide second term by first term
r=[tex]\frac{-10}{20} = -\frac{1}{2}[/tex]
now we plug in the values
[tex]S_n = \frac{20}{1-(-\frac{1}{2}}[/tex]
[tex]S_n = \frac{20}{1+\frac{1}{2}}[/tex]
[tex]S_n = \frac{20}{\frac{3}{2}}[/tex]
[tex]S_n = 20 * \frac{2}{3}[/tex]
sum = 40/3
