Toni is selling caps for the baseball club. The picture shows the number of caps that Toni sold during the first three weeks.
Week 1
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* * * * * * * * *
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Week 2
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* * * * * *
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Week 3
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* * *
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Week 4
|
?
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How many hats must Toni sell in week 4 so that the average number of caps that she has sold per week is 7?