In a school 2/3 if student study language and of those study 2/5 study French Find the ratio of student who study french and students who dont and give your answer in Simplest form

Afarmer has a large field that is x feet in length. he wants to fence in a rectangular section in the middle of the field , leaving a length of 100 feet of open field behind each end of the fenced rectangle.he also wants the width of the fenced-in space to be 100 feet less than its length. find the expressions to represent the length and width of the fenced section of the field