In: Advanced Math
3. The Krov band is touring the UK. They have played eight dates and already their tour is a great success. Total post-gig sales (merchandising, CDs etc.) on each date have been:
| 
 Date no.  | 
 Sales (£000s)  | 
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| 
 1  | 
 3  | 
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| 
 2  | 
 7  | 
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| 
 3  | 
 15  | 
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| 
 4  | 
 14  | 
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| 
 5  | 
 18  | 
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| 
 6  | 
 21  | 
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| 
 7  | 
 16  | 
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| 
 8  | 
 22  | 
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| 
 9  | 
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