but I have a headache. Here's the question: A laundry powder company wishes to produce a 27mm^3 washing powder capsule in the shape of a rectangular box. Due to production rescrictions, the width and the depth of the capsule must be equal lengths, and all dimensions of the capsule must be equal to at least 2mm. To ensure the rate at which the capsule is dissolved during washing, it is required that the surface areas of the capsule is as large as possible. What should the dimensions of the capsule be so that its surface area is maximised. I've got that if the width and depth = a, and the length = b, the volume = b*a^2 Therefore, 27= b*a^2, but where do I go from here.