Least to greatest 26/4, 6.45, 6 2/5, and 50/8

Write a recursive sequence that represents the sequence defined by the following explicit formula:

What is the greatest common factor of 8 and 36

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