Two similar solid statues are 20 cm and 30 cm tall. If the shorter one weighs 6 kg, how much will the taller one weigh?

Question

anonymous · Answer

weigh = volume

volume of A : volume of B = (length of A) ^3 : (length of B)^3

6:x=20^3:30^3
6/x = 20^3 / 30^3 
solve this to find x

p0sitr0n · Answer

$$6/x =(2/3)^3$$
$$6/(2/3)^3$$ =x
x =20.25

anonymous · Answer

how did you know to put 8000/27000?

anonymous · Answer

instead of 27,000/8,000

p0sitr0n · Answer

yeah true, but you can easuly reverse it and get 9kg as answer

anonymous · Answer

oh so it could be either one?

anonymous · Answer

my book has 20.25

anonymous · Answer

take a cube as an example,
(length of A)^3 = volume of A
(length of B)^3 = volume of B
volume of A/ volume of B = (length of A)^3 / (length of B)^3
so, it cannot be reversed!