400 out of the 900 students do not take the bus to school
Here, we want to know the number of students in the 7th grade that do not take a bus to school
Firstly, we need the fraction of the survey for students who do not take a bus
The total surveyed is 8+ 12 + 25 = 45
Out of this, (8+12 = 20) do not take the bus
The farction of the survey that do not take a bus is 20/45
So, out of the 900, the number that do not take a bus will be;
20/45 * 900 = 20 * 20 = 400 students
