Total letters in Mathematics=11
|S|=11
Now
Counting letters
[tex]\\ \sf\longmapsto P(M)=\dfrac{2}{11}[/tex]
[tex]\\ \sf\longmapsto P(A)=\dfrac{2}{11}[/tex]
[tex]\\ \sf\longmapsto P(T)=\dfrac{2}{11}[/tex]
[tex]\\ \sf\longmapsto P(H)=\dfrac{1}{11}[/tex]
[tex]\\ \sf\longmapsto P(E)=\dfrac{1}{11}[/tex]