4R Systems interview questions

Got a telephonic screen interview within a week of applying through email. Spoke to the one the top management guys Mr. Stephan Alberti. Initially we talked about the company and then the interview started with questions on probability. All the questions were on flipping coin and conditions with them(conditional probability). I answered the first 3 questions correctly but I missed something in the fourth question. Interviewer was very patient and he was giving me a lot of time to solve the problems. But since I took too long and couldn't answer the last one I got rejected. Rejection email came after a week of the interview. Interview was short.