A mole left its burrow 4 feet underground and started digging deeper into the ground. It digs straight down at a constant rate of 3 feet per minute. How long does it take the mole to reach 13 feet underground?

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