Answer
$\frac{3}{10}$
Work Step by Step
Sample space= {a,b,c,...,x,y,z}
Let E denote the event that the selected letter is a vowel and F be the event that the letter precedes k.
We have to find P(E|F).
E= {a,e,i,o,u} , F= {a,b,c,d,e,f,g,h,i,j}
and E∩F= {a,e,i}.
P(F)= $\frac{10}{26}$ and P(E∩F)= $\frac{3}{26}$
We know that P(E|F)=$\frac{P(E∩F)}{P(F)}=\frac{3/26}{10/26}= \frac{3}{10}$