A JEE aspirant estimates that she will be successful with an 80 percent chance if she studies 10 hrs. Per day, with a 60 percent chance if she studies 7 hrs. Per day and with a 40 percent chance if she studies 4 hrs. Per day. She further believes that she will study 10 hrs. 7 hrs. and 4 hrs. per day with probabilities 0.1, 0.2 and 0.7, respectively.
(a) What is the chance that she will be successful?
(b) Given that she is successful, What is the chance that she studies for 4 hrs?
(c) Given that she does not achieve success, What is the chance that she studies for 4 hrs?