15. Five mark exercise problems - IV

In a class of \(35\), students are numbered from \(1\) to \(35\). The ratio of boys to girls is \(4:3\). The roll numbers of students begin with boys and end with girls. Find the probability that a student selected is either a boy with a prime roll number or a girl with a composite roll number or an even roll number.Answer:

 

The required probability is $\frac{i}{i}$.