at t=o an evenly mixed 40 liters solution with 100grams of salt is poured into a container. solution comes in at 2 grams per liter at 3 liters per minute and flows out at the same rate. At what time is the salt solution 120 grams? I got -9.something minutes for my answer :/ This question was on a test I just took. It's from memory. The linear equation I got was dA/dt+3/40*A=6 What should the answer be?