A resevoir contains 700 liters of pure water. Brine contaning 0.02 kg/L of salt enters at a rate of 5 L/min. Another source of brine contanining 0.05 kg/L enters at a rate of 2L/min. The resevoir is well mixed and drains at a rate of 7L/min.How much salt is thier in the resevoir (i) after t min (ii) after 10 min?

Can anyone please help me start of this problem much thanks!