15. The duration of flights between two locations is normally distributed with a mean of 6 hours and a standard deviation of 45 minutes. Approximately what percentage of these flights can be expected to take between 7 and 8 hours? A. 0.088 (4 marks) B. 0.098 C. 0.988 D. 0.889 16. A survey by the National Retail Federation found that women spend on average R146.21 on a Saturday lunch. Assume the standard deviation is R29.44. Find the percentage of women who spend less than R160.00 on a Saturday lunch. Assume the variable is normally distributed. (4 marks) A. 0.69 B. 0.59 C. 0.68 D. 0.95 17. A survey by the National Retail Federation found that women spend on average R146.on a Saturday lunch. Assume the standard deviation is R29.44. Find the percentage of women who spend less than R190.00 on a Saturday lunch. Assume the variable is normally distributed. A. 0.88 (4 marks) B. 0.74 C. 0.93 D. 0.82