Brittany gets a $14 allowance each week. She earns extra money by taking care of pets in her neighborhood. She earns $7 for every pet she takes care of. Each week, Brittany pays $4 for a music subscription and $3 for a movie streaming service. She also has a goal to save $35 a week for college. How many pets does Brittany need to take care of each week to reach her goal?