Abrine solution of salt flows at a constant rate of 3 l/min into a large tank that initially held 100 l of pure water. the solution inside the tank is kept well stirred and flows out of the tank at a rate of 2 l/min. if the concentration of salt in the brine entering the tank is 0.4 kg/l, determine the mass of salt in the tank after t min. when will the concentration of salt in the tank reach 0.3 kg/l?

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Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

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