A tank contains 4000 liters (L) of a solution consisting of 234 kg of salt dissolved in water. Pure water is pumped into the tank at the rate of 9 L/s, and the mixturelong dashkept uniform by stirringlong dashis pumped out at the same rate. How long will it be until only 13 kg of salt remains in the tank?

t≅23.24 s

Step-by-step explanation:

There is a tank with 4000 liters of a solution with 234 kg of salt, this means that 4000 lt of solution contains 234 kg of salt and 3766 liters of water, so you must find the amount of water and the time used to shift said volume

234*100/4000 = 5.85%, this means 5.85 kg of salt in 100 Lt of solution, so

(4000 sol/234 kg salt) * 13kg salt = 222.2 sol

that is, in order for 13 kg of salt to remain, 222.2 liters of solution must remain

, where 222.2sol-13kg salt = 209.2 Lt of water, with the rate of 9 Lt/s

we have 209.2Lt*s/9Lt ≅ 23.24 s

Note: tank filling speed is equal to tank drain rate