Question

Q. The probability of guessing the correct answer to a
certain test questions is x/12. If the probability of not guessing the
correct answer to the question is2/3, then x =
a) 2
b) 3
c) 4
d) 6

Answer 1

we know that
probability that event happens + probability that event does not happen = 1
x/12+2/3=1
x/12=1-2/3
x=(1/3)*12
x=4
Therefore option c is correct