Let height of cuboid = $$h$$ cm , length = 10 cm and breadth = 8 cm Volume of cuboid = $$lbh = 320$$ => $$10 imes 8 imes h = 320$$ => $$h = frac{320}{80} = 4$$ cm Total surface area of cuboid = $$2(lb+bh+hl)$$ = $$2[(10 imes 8)+(8 imes 4)+(4 imes 10)]$$ = $$2(80+32+40)$$ = $$2 imes 152 = 304$$ $$cm^2$$ => Ans - (B)