Hey, I was having trouble with these review word problems if someone could help me please, thanks!

Question 8 0.5 pts According to a survey of advanced curriculum high school students, the mean time spent studying each day is 6.4 hours. Assume the standard deviation is 0.80 hours and that the probability distribution is normal. What is the probability that a randomly selected student studies 6 hours per day or less? Round your answer to 2 digits after the decimal. D Question 9 0.5 pts According to a survey of advanced curriculum high school students, the mean time spent studying each day is 6.4 hours. Assume the standard deviation is 0.80 hours and that the probability distribution is normal. What is the 80th percentile for number of hours spent studying each day? Round your answer to 2 digits after the decimal.D Question 11 0.5 pts A cyber hacker is trying to identify the mean age of customers that make frequent purchases on the online retail platform. The hacker does not have access to the raw data, however, the hacker had guessed that the age of customers is normally distributed with a standard deviation of 5 years. In addition to the above, the hacker knows that 70% of the time the age of the customers does not exceed 30 years old. Calculate the mean age of customers, relying on the above information. Round to a whole number