This is very easy. If your gross was $500 then 60% of that gross would be $300. Since you have agreed to a guarantee of $125 which was also paid as an advance, you would then owe them a balance of $175. $500 x 60% = $300 - the $125 paid in advance as a guarantee leaving the $175 balance due.
If you gross the exact same amount the 2nd week the rental would be $500 x 50% or $250. The advance and guarantee should have been for the entire run of the film, not per week, therefore the 2nd week would be the straight percentage.
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