Nodia cuts 3 pieces of equal length from 8 yards of ribbon. how long is each piece? choices: 24 yards 5 yards 8/3 yards 1/3 yard (answer fast ! )

Ineed if you could explain and give me the answer you! this needs done

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

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'