In an exam of Chemistry, three students (X, Y and Z) participated and got an average score 80 . In another exam i.e. Maths, two students (X and Y ) got 20% more marks then in Chemistry exam while Z got 10% less marks relative to Chemistry exam. Average mark in Maths exam is six more than average marks in Chemistry exam. If difference between score of X and Y in Maths exam is 24 then find the average of all the three students in Biology exam if X and Y got 25% more marks in Biology than Maths exam while Z got only 10% more marks than Maths exam?