Q1. A cardboard box with a square base is to have a volume of 7 litres. (7L = 7000 cm') The cardboard for the box costs 0. 1c/cm , but the cardboard for the bottom is thicker, so it costs 5 times as much. Find the dimensions that will minimize the cost of the cardboard.' Solve each problem by first drawing a diagram with each side length as a variable, then finding the main equation, then have one variable on each side of the equal sign, if not find the second equation, re-arrange and substitute into main equation. Then derivate. Then set the equation to zero and solve