Posted by **kgosi** on Thursday, April 25, 2013 at 11:09am.

A water tank can be constructed with a metal top and two square ends that holds 16 cubic meter of water and requires 40 square meter of metal. find the dimensions of the water tank.

- math -
**Steve**, Thursday, April 25, 2013 at 11:16am
if the ends have side x, and the tank has height h,

x^2 h = 16

2x^2 + 4xh = 40

2x^2 + 4x(16/x^2) = 40

x^2 + 32/x = 20

x^3 - 20x + 32 = 0

(x-2)(x^2+2x-16) = 0

so, if x=2, the tank is 2x2x4

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