Let the sides of three metal cubes be 3x, 4x and5x respectively. Let the side of the single cube formed be a. Length of the diagonal of the cube a√3=48√3 ⇒a=48 meters Given the three cubes are melted and made into a single cube. ⇒ Volume of three cubes = Volume of cube ⇒(3x)3+(4x)3+(5x)3=a3 ⇒27x3+64x3+125x3=483 ⇒216x3=483⇒x=8 Required answer, the side of the smallest cube =3x=3×8=24m