Question

three solid metal cubes with edges 6cm,8cm and 10cm respectively are melded together and formed into a single cube.find the voume of new cube

Answer 1

Volume remains same so 
volume of new cube = v1+v2+v3
= 6^3+8^3+10^3
=216+512+1000
=1728
now volume of new cube = a^3= 1728

edge of new cube = a= cuberoot of 1728

a= 12

therefore surface area of new cube = 6 a^2
=6×12^2
=6×12×12
=864 square cm

Answer 2

Hey friend your answer is
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Q:-Three solid metal cubes with edges 6cm, 8 cm and 10cm respectively are melted together and formed into a single cube find the volume of the new cube.

Method of solution
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side of cube 1 = 6cm
volume of cube 1 =(6×6×6)cm³=216cm³

side of cube 2=8cm
volume of cube 2 = (8×8×8)cm³=512cm³

side of cube 3= 10cm
volume of cube 2= (10×10×10)cm³=1000cm³

Volume of metal of 3 cubes
=(216+512+1000)cm³
=1728cm³

•°•Volume of new cube =1728cm³
•°•side of new cube = ³√1728cm³
= ³√12×12×12cm
=12cm

$hope \: it \: help$