1. The problem statement, all variables and given/known data A 5 pound mixture of barley and oats is 4/5 oats by weight. How much barley in pounds must be added to the mixture to make it 3/5 oats by weight? 2. Relevant equations - 3. The attempt at a solution I honestly cannot figure this problem out. The book gives the answer and writes out the steps, but it does not help me one bit. The book does not explain how it arrived at the variables that it uses and, more importantly, I feel like I couldn't take its solution and understand it enough to use on any related type of problem. Here is the book's answer and basic steps: A: 1 and 2/3 pounds [1.66667 lbs]. First it converts the mixes into percents - original = 80% oats/20% barley; desired = 60% oats/40% barley. Then, i. (.8)(5)/5+b = 60% ii. (.8)(5)=.6(5+b) iii. 4 = 3 + .6b iv. b= 1/.6 v. b = 1 & 2/3 [1.6667] pounds of barley must be added. Please explain how to solve this type of problem. I can see the book's work and understand all the variables, but it doesn't make any sense to me. That is, I couldn't set up the solution to a new, similar problem. Thanks for the help!