If for 7 days the values of X and Y are (0.52,0.18), for 25 days the values are (0.09,0.08), and for 35 days the values are (0.07,0.08) then for which number of days the values of X and Y will be zero. Please also point out which day is the last day on which box X and Y are positive values? Please write the formulas clearly and give a reference of book e.g. extrapolation topic (page number or book). Don't show any negative numbers in the solution.

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