Kevin gives roping lessons at the Sundown Corral. A 3.5-hour lesson costs $52.50. The cost of a lesson is proportional to the duration, in hours, of the lesson. What is the constant of proportionality in terms of dollars per hour? A. 25 B. 10 C. 15 D. 20

The number of chocolate chips in a bag of chocolate chip cookies is approximately normally distributed with a mean of 12611261 chips and a standard deviation of 118118 chips. (a) determine the 2626th percentile for the number of chocolate chips in a bag. (b) determine the number of chocolate chips in a bag that make up the middle 9696% of bags. (c) what is the interquartile range of the number of chocolate chips in a bag of chocolate chip cookies?