9514 1404 393
Answer:
A. 10 weeks
Explanation:
Marie's balance is initially $100 less, but she deposits $10 more per week than Oliver does. It will take her 100/10 = 10 weeks to catch up to Oliver's balance.
Oliver and Marie will have the same balance after 10 weeks.
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Oliver's balance at that time will be 300 +10×10 = 400.
Marie's balance at that time will be 200 +10×20 = 400. (the same)