First, we have to sum the fractions she already read.
[tex]\frac{3}{10}+\frac{1}{2}=\frac{6+10}{20}=\frac{16}{20}=\frac{8}{10}=\frac{4}{5}[/tex]
This means Ana already read 4/5 of the journal, the missing quantity is the complement fraction to 4/5, which is 1/5.
Hence, she still needs to read 1/5 of the journal.
