ASAP PLSSS help me with this math question

What does the relationship between the mean and median reveal about the shape of the data

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?