technically speaking this sum is meaningless!
it says it rains as many days as there are rain free days:
so lets take rainy days as 30
dry days ;)as 10
Its obvious that the whether forcasting thing would predit;it would rain
30 days out of the total 40 days.(not less than dat)
but it says out of there is 1/10 chance that they are wrong :O
so out of the 30 days:
30 x 1/10 of days could be wrong(i.e it wouldn't rain if they say it would)
so 3 days are gone dry
since it rains 30 days anyway 3 days should rain !!
out of the 10 dry days:
10x9/10 is dry so 9 days are dry :
10 x 1/10 of days could be wrong(i.e it would rain if they say it wouldn't)
only one day could rain here ! i.e for prediction to be wrong
but theres 3 left!!
just correct me if i hav understood the sum wrong ,or if i'm wrong
in my calculations
because i havent done math