Students in Mrs. Crosby's third grade class are working on times tables, and they demonstrate mastery by passing tests. Sadie has passed 2 tests so far. Her classmate, Deion, has passed 6 of them. From now on, Sadie plans to take and pass 4 tests per week. Meanwhile, Deion plans to do 2 per week. At some point, Sadie will catch up to Deion. How long will it take?