Total number of students in classes 4, 5 and 6 are 100. The average scores of students in class 4 and class 6 are 70 and 95 respectively. The average scores of students in class 4 and class 5 combined is 83 and the average scores of students in class 5 and class 6 combined is 87.5. Find the number of students in class 4 if it is given that the average of the scores of the students in all the classes is 84.