Set up only, no need to solve. I am looking for a thoughtful model for this so be sure your boundaries are carefully shown in diagrams.A tank contains $1000$L of pure water. Brine that contains $0\mathrm{.}05$ kg of salt per liter of water enters the tank at a rate of $5$L$/$min$.$ Brine that contains $0\mathrm{.}04$kg of salt per liter of water enters the tank at a rate of $10$L$/$min$.$ The solution is kept thoroughly mixed and drains from the tank at a rate of $15$L$/$min$.$ How much salt is in the tank after t minutes?