A jeweler has 5 rings, each weighing 14 g, made of an alloy of 15% silver and 85% gold. She decides to melt down the rings and add enough silver to reduce the gold content to 70%. How much silver should she add?

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