A class has 175 students. The following description gives the number of students studing one or more of the subjects in the class Mathematics 100,Physics 70,Chemistry 46,Mathematics and Physics 30, Mathematics and Chemistry 28, Physics and Chemistry 23, Mathematics,Physics and Chemistry 18. Find (i) How many students enrolled in mathematics only ? (ii) How many enrolled in exactly two subjects ? (iii)How many enrolled in atleast one subject? (iv) The number of students who have not offered any of these subjects.