Question

27. Three solid cubes of type A and three
solid cubes of type B are melted to form
a cube. If the lengths of diagonals of
cubes of type A and type B are 4/3cm
and 8/3cm respectively, then find the
lateral surface area of the cube so
formed.
(A) 625 cm? (B) 864 cm?
(C) 576 cm
(D) 784 cm
(E) None of these​

Answer 1

Length of diagonal=a√3

type A's diagonal=a√3=4/3-----(1)

a=4/3÷√3

a=4/3√3=2.3094010767585

type B's diagonal=a√3=8/3------(2)

a√3=8/3

a=8/3÷√3

a=8/3√3=4.6188021535170

Lateral surface=4a^2

type A

4×(2.3094010767585)^2= 21.333333333333276835469289

type B

4×(4.6188021535170)^2= 85.333333333333107341877156

Lateral surface of cube formed by A and B is

type A + type B lateral surface

3×21.333333333333276835469289+3×85.333333333333107341877156

=319.999999999999152532039335

319.9 is not there so none of these

I think check other's answer too