Hi civiliam.

In this case you got to use the binomial distribution with p=0.35 so it is 1-p = 1 - 0.35 = 0.65

So have to calculate

Probability("on 30 days there is no hair on your food") =

Probability("on 30 days you find on one day a hair")=

.

.

.

.

.

Probability("on 10 days out of 30 you find some hair") =

And now you have to add all this probalilities to find probability(10 or less times you find some hair in 30 days) = prob(no hair was found) + prob(one time hairs were found) + prob(two times hairs were found) +prob(three times hairs were found) + ... + prob(ten times hairs were found)

Yours

Rapha