Use the cosine function.
cos x = 2/12
cos x = 0.167
use the inverse of cosine:
x = 80.405
The answer is C.
Hope this helps :)
11.22 is 33% of 34 if that is what youre asking
Since she has seven key the probability that the first one will open the door is

if it takes three attempts to open the door,the probability is

if the three attempts would not work
then the probability that the fourth attempt will open the door is

hope this helps
P(arrives on time given leaves on time)=
P(B | A)= P(B n A) / P(A)
= P(A n B) / P(A)
= 0.36 / 0.9
= 0.4