How many weeks will the cat food last?

The answer is: Two (2) weeks.
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Explanation: 
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Anne has:
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¾ of a bag; or ¾*(1b); or, (¾)b ; which: b = number of bags of cat food.
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Anne's furry and purry little friend eats:
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[(⅜)b] / wk ;  in which: "wk" = weeks(s).
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So, how many "weeks"; or, "wk", will the cat food last?  We want our answer to be in "wk".
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→  {1 wk / [(⅜)b] } *[(¾)b]  = ?  wk. ?
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→ The unit symbols, "b", cancel to "1"; and we have:
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→  [1 wk *(¾)] / [(⅜)]  = [(¾) wk] / [(⅜)]
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→  = [(¾) / (⅜)] wk.
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→     ÷     
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→     =     *     ;
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→ The "3's" 'cancel out. to "1's". 
   The "4"  change, and the "8" changes to a "2" (since "8÷4 = 2").
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→ And we are left with:
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→    *    ;
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→  = 1 * 2 
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= 2 wks. ; → The answer is: Two (2) weeks.
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