Answer:
2 Weeks
Step-by-step explanation:
Sadie is currently behind Deion by 4 tests (6 - 2). Since Sadie plans to take and pass 4 tests per week, and Deion plans to do 2 per week, the gap between them will decrease by 2 tests each week (4 - 2).
Therefore, it will take Sadie 2 weeks to catch up to Deion (4 tests gap ÷ 2 tests reduction per week).