A tank contains 1000 l of pure water. Brine that contains 0. 05 kg of salt per liter of water enters the tank at a rate of 5 l/min. Brine that contains 0. 04 kg of salt per liter of water enters the tank at a rate of 10 l/min. The solution is kept thoroughly mixed and drains from the tank at a rate of 15 l/min.

Asociologist chose 300 students at random from each of two schools and asked each student how many siblings he or she has . the result are shown in the table below. there are a total of 2,400 students at lincoln school and 3,300 students at washington school .what is the median number of siblings for all the students surveyed ? a)0b)1c)2d)3