In a group of \(145\) students, the numbers studying mathematics, physics and chemistry are given below. All students study at least one of the three subjects.

\(x\) students study all \(3\) subjects.

\(24\) students study both mathematics and chemistry.

\(23\) students study both physics and chemistry.

\(28\) students study both mathematics and physics.

\(50\) students study chemistry.

\(75\) students study physics.

\(80\) students study mathematics.

(i) Using the Venn diagram, find the value of \(x\).

(ii) Find the number of students who study mathematics only.