A weatherman states that the probability that it will rain tomorrow is 10%, or 0.1, & the probability that it will snow is 25%, or 0.25. What is the probability that it will not rain or snow?

• A. $0.35$
• B. $0.65$
• C. $0.75$
• D. $0.90$

Answer: (B)

Verified step by step guidance

1. Identify the given probabilities: the probability of rain (P(Rain)) is 0.1 and the probability of snow (P(Snow)) is 0.25.
2. Understand that the problem asks for the probability that it will not rain or snow. This is the complement of the event that it will either rain or snow.
3. Calculate the probability of rain or snow using the formula for the union of two events: P(Rain or Snow) = P(Rain) + P(Snow) - P(Rain and Snow).
4. Assume that rain and snow are independent events, meaning P(Rain and Snow) = P(Rain) * P(Snow). Calculate this value.
5. Find the probability that it will not rain or snow by taking the complement of the probability that it will rain or snow: P(Not Rain or Snow) = 1 - P(Rain or Snow).