If you were to create a histogram from the data shown in the stem-and-leaf plot, with each bar covering six values from 13 to 42, how many bars would there be? A) 2
B) 3
C) 4
D) 5
E) 6

Photo attached below :)

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

Math i have no idea how to do a and b

How can writing phrases as algebraic expressions you solve problems?