Your question is Double-Headed Coin Posterior. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
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?