A survey of young people’s shopping habits in a small city during the summer months of 2015 showed the following: Shoppers aged 12 to 14 years took an average of 8 shopping trips per month and spent an average of $14 per trip. Shoppers aged 15 to 17 years took an average of 11 trips per month and spent an average of $18 per trip. Assume that this city has 1100 shoppers aged 12 to 14 years and 900 shoppers aged 15 to 17 years.
a. Find the total amount spent per month by all these 2000 shoppers in both age groups.
b. Find the mean number of shopping trips per person per month for these 2000 shoppers.
c. Find the mean amount spent per person per month by shoppers aged 12 to 17 years in this city.