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.