PLEASE HELP WITH THIS, answer all parts, ill give u a lot of points and mark u brainliest

Will give brainliest sum of arithmetic series (sigma notation) find the numerical answer to the summation given below. (image shown 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

Joe has a rectangular chicken coop. the length of the coop is 4 feet less than twice the width. the area of the chicken coop is 510 square feet. what is the length of the chicken coup?