Probability question help? Suppose I watch the six oclock news 2/3 of the time and the 11 o\'clock news 1/2 the time and watch both news 1/3 of the time. What is probability that I watch only the six o\'clock news? this question comes from a chapter in my textbook that focused on properties of probability like total probability, sub-additivity, monotonicity and principle of inclusion-exclusion. am i suppose to use one of these properties to answer the question? Solution P(only six) = P(six)-P(both) = 2/3 - 1/3 = 1/3 ANSWER: 1/3.