Question

A solid metallic rod 15 cm long with diameter equal to 3.5 cm is melted and made in to another rod of radius 3.5 cm what will be the length of the new rod

Answer 1

15 x 3.5/2 x 3.5/2 x 3.14 = l x 3.5 x 3.5 x 3.14
15 x 3.5/2 x 3.5/2 x 3.14/3.14 = l x 12.25
15 x 12.25/4x12.25 = l
15 x 1/4 = l
15/4 = l
3.75 = l

Answer 2

here is the solution