Answer:
0.27
Explanation:
Since it's given that the student is dropped off by parents, we can ignore all the students who take the bus, so our total population is 0.45. So now we just take the seventh grade students, 0.12, and divide by the total students whose parents drop them off, 0.45.
0.12/0.45 = 0.266666, round up to 0.27.