A rain gutter is to be made of aluminum sheets that are 16 inches wide by turning up the edges 90. See the illustration. (a) What depth will provide maximum cross-sectional area and hence allow the most water to flow? (b) What depths will allow at least 30 square inches of water to flow? (a) The depth that will provide the maximum cross-sectional area is inches. (b) The depths between in. and in. will allow at least 30 square inches of water to flow