A tank contains 1000L of pure water. Brine that contains 0.02kg of salt per liter enters the tank at a rate of 5L/min. Also, brine that contains 0.07kg of salt per liter enters the tank at a rate of 10L/min. The solution is kept thoroughly mixed and drains from the tank at a rate of 15L/min. Answer the following questions. a. How much salt is in the tank after t minutes?
b. How much salt is in the tank after 4 hours?

51.877 kg

Step-by-step explanation:

a

See attachment for calculations

b

The amount of salt in the tank after 4 hours is gotten by simply replacing t in the equation from a, with 4 hours. Since the t gotten in a above is in minutes, we'd convert hours to minute as well. If we do that, we have

t = 4 hours = 4 * 60 minutes = 240 minutes

y = 160/3 (1 - e^((-3 * 240)/200))

y = 160/3 (1 - e^(-720/200))

y = 160/3 (1 - 0.0273)

y = 160/3 (0.9727)

y = 51.877 kg

Therefore, the amount of salt in the tank after 4 hours is 51.877 kg

2nd one in the first row is correct