Answer:
[tex]\frac{14}{5}[/tex] or 2.8
To find [tex]S_4[/tex] we use formula:
[tex]S_n=\frac{n}{2}*(2a_1+(n-1)*d)[/tex]
D = [tex]\frac{2}{5}[/tex]
[tex]a_1=\frac{1}{10}[/tex]
[tex]n=4[/tex]
Hope this helps!!!
