Help!! A farmer estimated that there were 25 gallons of water left in a tank. if this is an underestimate by 16%, how much was actually in the tank?​

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