Weekend just includes Saturdays and Sundays, so you don't have to count the earnings on Friday. You simply have to count the number of hours that passed from 7 am to 11 pm on Saturday. That would be a total of 16 hours. While on Sunday, the time from 9 am to 9 pm is a total of 12 hours. Hence, the total time would be 16 hours + 12 hours = 28 hours
B - line graph. A line graph should be added because he wants to know how many of available apartments there were during the time of the year and line graphs are usually up and down on the info.