A tank contains $1000\text{L}$ of brine with $15\text{kg}$ of dissolved salt. Pure water enters the tank at a rate of $15\text{L/min}.$ The solution is kept thoroughly mixed and drains from the tank at the same rate. Answer the following questions.

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1. How much salt is in the tank after $t$ minutes?
Answer (in kilograms): $S(t) =$

2. How much salt is in the tank after $10$ minutes?
Answer (in kilograms):

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