At a busy intersection, the speed of a number of passing cars in km/h-1is recorded and the information is represented in the cumulative frequency graph shown below.

At a busy intersection, the speed of a number of passing cars in km/hid is recorded and the information is represented in the cumulative frequency graph shown below. 50 - 45- 40 35 'S Cumulative frequency 25 20 15 - 10 - 5- o+ 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Speed of cars (km/h)(a) How many cars were included in the data sample? [1 mark] (b) (i) If the speed limit at the intersection is 40km/h, how many cars are driving above the speed limit? [2 marks] (ii) State the median and interquartile range for the speeds of the cars and interpret your results. [6 marks] (iii) The slowest 10% of all drivers are issued a large fine for slowing down traffic. What is the maximum speed to drive at to be issued the fine for driving too slowly? [2 marks]