please help with number 3

3) The recommended dissolved oxygen (DO) concentration to maintain healthy fish is between 6 and 8Lmg. a) Aim for a DO concentration of 7Lmg. Determine what oxygen saturation level (give as \%) in water this implies under ambient conditions in Gauteng. You may make the following assumptions: - The water temperature is 21C and atmospheric pressure is Patm=87kPa - Use =1000kg/m3 for the density of water - Assume ideal gas behaviour for oxygen ( MM=32 ) and nitrogen ( MM=28 ) Henry's constant for oxygen in water at this temperature is HO2=4.02106molfractionkPa b) Determine the saturation concentration of Nitrogen (also in Lmg ) under the same conditions as those listed above. HN2=76.48molfractionkbar