3道英文版的代数题,

题目

3道英文版的代数题,
A parking lot charges $10 to park for the first day or part of a day.After that,it charges an additional $8 per day or part of a day.Describe the graph and find the cost of parking for 6.5 days.
The current in a river is 6 miles per hour.In her motorboat Marissa can travel 12 miles upstream or 16 miles downstream in the same amount of time.What is the speed of her motorboat in still water?
Adam,Bethany,and Carlos own a painting company.To paint a particular house alone,Adam estimates that it would take him 4 days,Bethany estimates 5.5 days,and Carlos 6 days.If these estimates are accurate,how long should it take the three of them to paint the house if they work together?

答案

1.停车场第一天收10块,以后每天收8块(不足一天按一天算),停6.5天收58块2.河水流速每小时6英里,M同学开摩托艇,同样时间内,顺水开16英里,逆水开12英里,问静水速度.56英里/小时3A.B．C三位同学刷房子,A同学单独刷要4天,...