A cabinet has 6 surfaces including the bottom surface. However, we have to paint only 5 surfaces. So, we have one front and one back surface (2 × 1.5), one left and one right surface (1 × 1.5), and one upper surface (2 × 1). So, the area to be painted is = (2 × (2 × 1.5)) + (2 × (1 × 1.5)) + (2 × 1) = 6 + 3 + 2 = 11 sq. m