The length of each edge of a cube is decreased by 40%. By what percent does the volume of the cube decrease? Express your answer to the nearest tenth.

Cube volume = x * x* x = x^{3}

now change to .6x

.6 x * .6x * .6x = .216 x^{3 }

^{It is now .216 of its original volume a dcrease of 1 - .216 = .784 or 78.4 % decrease }