i kindly need your help because i have only 30 minutes to answer this and i cant figure them out. :(

Problem: Daily water intake (including water used in drinks such as coffee, tea and juice) for adults follows a normal distribution with mean 1.67 litres and standard deviation 0.27 litres.

a) Using the 68-95-99.7 Rule, approximately 95% of samples of 28 adults will have mean daily water intakes between ____ and _____ (Answer could be within 4 decimal places or No.)

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Problem: Service times for customers at a post office follow some right-skewed distribution with mean 2.58 minutes and standard deviation 1.74 minutes.

a) Can you calculate the probability that the average service time for the next two customers is less than 2.31 minutes? If you can, enter the probability in the answer box. If you can't, type the word No.

b)What is the probability that the total service time for the next 43 customers exceeds 126.69 minutes? (Assume that the next 43 customers represent a simple random sample and that there is always a customer waiting in line.)