Reds varied directly as yellows and inversely as greens squared. If 100 reds and 40 yellows went with 10 greens, how may reds went with 20 yellows and only 5 greens?

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