Answer:
A. 600
Explanation:
from the interquartile range of johnsonia skl, u can tell that 50 percent of their students spent 20-30 hrs. we also know the same number of studenst spent 20-30 hrs in flowerdale. flowerdale shows that the bottom 25 percent of their skl spent 20-30 hrs, so 50% of johnsonia = 25% of flowerdale.
50 percent of johnsonia is 100 (200/2) and that means a quarter of the students in flowerdale = 100 students, so in total they have 400 students doing driving lessons.
400 students + 200 students = 600 students