According to data from facebook.com, in 2016 the average amount of time that users spend each day on Facebook, Instagram, and Messenger platforms is 50 minutes. Assume the data for time spent follow the normal distribution with a standard deviation of 14.5 minutes.

a. What is the probability that a random customer spent

1. less than 30 minutes on these social media?

2. more than 45 minutes on these social media?

3. between 50 and 90 minutes on these social media?

4. between 65 and 85 minutes on these social media?

b. Use Excel to confirm the answers in part a.

c. How many minutes on these social media are in the 35th percentile?