Question

A cubical block of metal weighs 6 pounds. How much will another cube of the same metal weigh if its sides are twice as long?

Answer 1

you have any ideas?

Answer 2

assume that the cubical block's sides measures are all x:
volume = x*x*x = x³
if the sides measures become doubled, each side will become 2x:
volume = 2x*2x*2x = 8x³
so the volume will increase 8 times if the sides are doubled, and since volume is directly proportional to weight ---> weight increases by 8 times:
6*8 = 48 pounds