A tank contains 80 grams of salt dissolved in 500 L of water. The inflow per minute is 20 g of salt dissolved in 20 L of water. The outflow is 20 L/min of the uniform mixture. 4. Which of the...

Hi! I badly need answers to these two questions (4 and 5). It woul be really appreciated if I received the answer in at most 30 minutes. Thank you in advance!

Extracted text: A tank contains 80 grams of salt dissolved in 500 L of water. The inflow per minute is 20 g of salt dissolved in 20 L of water. The outflow 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)? dm А. dt m + = 20 25 dm + 20m = 20 dt dm С. dt m =1 25 dm dt + 20m = 1 D. 5. Find the time (in minutes) at which the salt content of the tank will reach 475 grams. а. 82.41 b. 53.82 c. 61.95 d. 70.53 B.