Given that, l = 10 m, b = 5m, h = 3m

lb =\( \Large 10 \times 5 \) = 50, bh = \( \Large 5 \times 3 \) = 15, lh = 10 x 3 = 30

Therefore, Surface area of a cuboid

= \( \Large 2 \left(lb+bh+lh\right) \)

= \( \Large 2 \left(50+15+30\right) \)

= \( \Large 2 \times 95 = 190 sq m. \)