13. amir and omar are tiling an area measuring a square meters. they lay down n tiles per square meter. omar can put down q tiles in r hours while it takes amir m minutes to lay one tile. a, n, q, r, and m are constants. (a) give the number of tiles amir and omar can put down as a function of t, the number of hours they work together. (b) how many square meters can they tile in t hours? (c) after h hours of working with omar, amir leaves. the job is not yet done. how many hours will it take omar to finish the job alone? express the answer in terms of any or all of the constants a, n, q, r, m, and h.

Self-interest achieve society’s economic goals because producers know which goods consumers want the most. as consumers and producers exercise their freedom to act in their own self-interest, markets will produce the desired goods at the lowest possible cost. consumers and producers both operate based on society’s economic goals. consumers know which goods can be produced at the lowest cost. there is a wide variety of desired goods and services in a market system because producers determine what to produce. consumers change their minds frequently. there is always a need to produce something new and improved. individual wants are diverse. what is produced is ultimately determined by consumers, because if the goods offered are not what consumers want, consumers will not buy them. producers, because they are driven by profits. producers, because they determine what to produce. consumers, because they participate in marketing surveys.