Leah would like to earn at least $125 per month. They babysit for $5 per hour and work at an ice cream shop for $7 per hour. Leah cannot work more than a total of 21 hours per month. Let x represent the number of hours Leah babysits and let y represent the number of hours Leah works at the ice cream shop.
If Leah babysits for 11 hours this month, what is the minimum number of hours they would have to work at the ice cream shop to earn at least $125?