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The probability it will rain is 40% each day over a three day period. What is the probability it will NOT rain at least one of these 3 days?
I got 60%, but this seems too simple. Is my answer correct??
2 Answers
- ?Lv 57 years ago
For the three days it will rain or not rain.
The negation is it rains all 3 days. The probability of that is 0.4^3=0.064
The probability it will not rain at least one of the days is 1-0.064=.936
- PuzzlingLv 77 years ago
Any time you see "at least one", consider the opposite case.
First, figure out the probability it will rain ALL 3 days:
0.4 x 0.4 x 0.4 = 0.064
= 6.4%
The opposite probability (of it raining all 3 days) is that it doesn't rain at least one of the 3 days.
1 - 0.064
= 0.936
Answer:
P(doesn't rain at least one day) = 93.6%
