MathematicsMedium175×since 2002Q2664Consider a cuboid of sides 2x, 4x and 5x and a closed hemisphere of radius r. If the sum of their surface areas is a constant k, then the ratio x : r, for which the sum of their volumes is maximum, is :A2 : 5B19 : 45C3 : 8D19 : 15Check answerSkip