A tank contains 5,000 L of brine with 11 kg of dissolved salt. Pure water enters the tank at a rate of 50 L/min. The solution is kept thoroughly mixed and drains from the tank at the same rate. (a) How much salt is in the tank after t minutes? y = kg (b) How much salt is in the tank after 20 minutes? () y = kg

a

b

Step-by-step explanation:

From the question we are told that  

    The volume of brine in the tank is  

     The mass of the salt is

     The rate at which water enters that tank is

Generally the rate at which salt enters the tank is mathematically represented as

=>        

Here the zero implies that there is no salt entering the tank

Generally the rate at which salt leaves  the tank is mathematically represented as

=>                

=>        

Generally the rate of salt flow in and out of the tank is              

=>    

=>    

=>    

at time  t = 0  y(0) =  11

=>  

=>  

So

taking exponent of both sides

=>  

=>  

Generally at t = 20 minutes

 The amount of salt in the tank is mathematically represented as

=>