Let the total marks are 100.
And Bradely got 66% marks.
So the marks of Bradely are:
[tex]\begin{gathered} M_B=\frac{66}{100}\times100 \\ M_B=66 \end{gathered}[/tex]And Zevel got one third of Bradely's marks so:
[tex]\begin{gathered} M_Z=\frac{1}{3}M_B \\ M_Z=\frac{1}{3}\times66 \\ M_Z=22 \end{gathered}[/tex]