Jean has $280 in her savings account. starting next week, she will deposit $30 in her account every week. is the amount of money in her account proportional to the number of weeks

No, this is not proportional. After 1 week she would have $280+$30=$310. After 2 weeks she would have $310+$30=$340. The proportional time is "2 to 1", but the proportional savings is $340 to $310, which is a different proportion.