Question

three cubes of silver with edges 3 cm, 4 cm and 5 cm are melted and recast into a single cube. find the cost of coating the surface of the new cube with gold @ rupees 3.50 per square cm

Answer 1

volume of first cube= 3×3×3
=27
Volume of 2nd cube=4×4×4
=64
Volume of 3rd cube=5×5×5
=125
Sum= 27+64+125
=216
cube root of 216 = 6
Total cost = 6×3.50
=21.
Therefore, 21Rs.

Answer 2

volume of the first cube=3*3*3=27
volume of the second cube=4*4*4=64
volume of the third cube=5*5*5=125
volume of the recasted cube=27+64+125=216
edge of the new cube=6
surface if the new cube=216
coast of coating=216*3.50=756Rs