Welcome to your interview.
The question is on your right: Double-Headed Coin Posterior. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
Solve this probability brain teaser: You have a bag of 100 coins, one of which is double-headed. You pull one out and flip it 10 times, getting heads every time. What is the probability that you chose the double-headed coin?