Reena studies for 4 hours, 6 hours, 2 hours, and 8 hours respectively for four consecutive days. How many hours did she study daily on an average?
Raj studies for 3.2 hours every day and he studied for two and a half weeks. How many hours did he study in total?
A jee aspirant estimates that she will be successful with an 80% chance if she studies 10 hours per day, with a 60% chance if she studies 7 hours per day and with a 40% chance if she studies 4 hours per day. She further believes that she will study10 hours, 7 hours and 4 hours per day with probabilities 0.1, 0.2 and 0.7 respectively Given that she does not achieve success, the probability she studied for 4 hours is