Alright.
So, we have 2185 student in Rose.
Lily School has 307 more students than Rose, so Lily has,
2185 + 307 = 2492 Students in Lily School.
Since question a. is asking you to round off to the nearest ten, your answer to part a is 2490.
For part b. add 2185 and 2490.
2185 + 2490 = 4675 students.
The questions want you to round to the nearest hundredth, so,
4700 is the answer to part b.