A tank holds 2500 litres of water in which 6000 grams of salt has been dissolved. Brine which contains 3 grams of salt per litre is run in at a rate of 25 litres per minute. (See below for a picture of the tank). The solution is thoroughly mixed and is extracted from the tank at the same rate. Letx be the number of grams of salt in the tank after 1' minutes. Based on the information given . Initially there are grams of salt in the tank. . salt is being added to the tank at a rate of grams per minute . the number of litres in the tank at time t is w . The salt is evenly distributed in the tank by mixing. Hence if there are x grams of salt in the tank, then one litre taken from this x tank contains :] E] grams of salt, and 25 litres contains W grams of salt. The change in salt with respect to time is described by the differential equation % = inow outow = 75