I need the answer as soon as possible

A A tank contains 80 grams of salt dissolved in 500L of water. The inflow per minute is 20 g of salt dissolved in 20L of water. The outfiow is 20 L/min of the uniform mixture. 4. Which of the following equations relates the mass of salt m (in grams) in the tank and the time t (in minutes)? + s = 20 + 20m = 20 + % = 1 + 20m = 1 B dw 1 dhi C. d! dm D df 5. Find the time (in minutes) at which the salt content of the tank will reach 475 grams