Explanation
Step 1
find the total Heather spends
[tex]\begin{gathered} \text{tottotal spent=food}+\text{rent} \\ \text{replace} \\ total\text{ spent=}\frac{1}{8}+\frac{9}{24} \end{gathered}[/tex]add the fractions
[tex]\frac{1}{8}+\frac{9}{24}=\frac{1}{8}+\frac{3(3)}{3\cdot8}=\frac{1}{8}+\frac{3}{8}=\frac{4}{8}=\frac{1}{2}[/tex]it means Heather spent 1/2 of her salary on food and rent
Step 2
now, find the fraction of her salary remains after she has paid:
as she spent a half of her salary, now she will have half
so
[tex]\begin{gathered} \text{salary remaining=salary-}\frac{1}{2}\text{salary} \\ \text{salary remaining=}\frac{1}{2}\text{salary} \end{gathered}[/tex]threfore the answer is
[tex]\frac{1}{2}of\text{ her salary}[/tex]I hope this helps you
