The probability that it will not rain for the next two weeks is 0.68 or 68%.
What is the probability?
The probability of rain this week is 0.20. According to the report, if it rains this week, then the probability of rain next week is 0.31. If it does not rain this week, then the probability of rain next week is 0.15.
To find the probability that it will not rain for the next two weeks we multiply the probabilities along the path of no rain:
The probability of no rain for the next two weeks is:
(1 - 0.20) * 0.85
= 0.68
Therefore, the probability that it will not rain for the next two weeks is 0.68.