We emailed out a survey to 50 random customers. So far we received 10 responses back. For one of the Yes/No questions, question 7, we got 10 yes's and 0 No's.

Mathematically, what is the probability that all 50 surveys will have yes's for question 7?

What would be the number n we could put in the following statement:

"We are 95% confident at least n surveys will have question 7 answered as a yes"?