Melanie's weekly allowance is $18
Step-by-step explanation:
let Melanie allowance = b
She spent half of it on movies = 1/2 × b = b/2
Amount left after removing movie cost = b - b/2
Then earned an additional $9 = (b - b/2) + 9
The total money Melanie has now = $18
b - b/2 + 9 = 18
![\begin{gathered} (b)/(1)-(b)/(2)+9=18 \\ (b)/(1)-(b)/(2)=18-9 \\ (2b-b)/(2)=9 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/rgw28ax7ns7k93xf8bwhpfas3qlswndbxr.png)
![\begin{gathered} (b)/(2)=\text{ 9} \\ b\text{ = 9(2)b } \\ b\text{ = 18} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/xgzryf7gbbognyginbudo8qtne50y9nw72.png)
Hence, Melanie's weekly allowance is $18