15. Five mark exercise problems III

In a class, all students take part in either music or drama or both. $25$ students take part in music, $30$ students take part in drama and $8$ students take part in both music and drama. Then,

 

(i) The number of students who take part in only music $=$

 

(ii) The number of students who take part in only drama $=$

 

(iii) The total number of students in the class $=$