Ruth lives in a place where it rains an average of 12 days out of 90. (continued down there)?

Question

. If the weather each day is independent of the previous day's weather, what is the probability that it will not rain 3 days in a row? Round to nearest whole percent.

Please show work :)

Answer 1

The question is ambiguous.

p = 12/90 = 2/15

The probability that it will rain for three days in a row is (2/15)^3, so the probability that it will NOT rain for three days in a row is

1 - (2/15)^3 ≈ 0.9976

On the other hand the probability that it will not rain on any given day is 13/15, so the probability that three days will pass without rain is

(13/15)^3 ≈ 0.6510