Given:
The amount of money you and your sister has is $60 and $120 respectively.
and your saving $7 per week and your sister saving is $5 per week.
Let, w denote the number of weeks.
[tex]\begin{gathered} A=60+7w\ldots\ldots..(1) \\ A=120+5w\ldots\ldots\ldots\text{.}(2) \end{gathered}[/tex]To find the number of weeks for you and your sister to have same amount of money,
[tex]\begin{gathered} 60+7w=120+5w \\ 7w-5w=120-60 \\ 2w=60 \\ w=30 \end{gathered}[/tex]Answer: 30 weeks.
