Please help me with this one

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

What numbers are included in the set of integers? what numbers are not included?

The functions f(x) and g(x) are shown in the graph f(x)=x^2 what is g(x) ?