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Three number are in the ratio $2:3:4$. The sum of their cube is $0.334125$, find the numbers.
Given: Three number are in the ratio $2:3:4$. The sum of their cube is $0.334125$.
To do: To find the numbers.
Solution:
Suppose the numbers $= 2x,\ 3x,\ 4x$
Given, the sum of their cubes $=0.334125$
As given, The sum of their cube is $0.334125$.
$( 2x)^3+( 3x)^3+( 4x)^3=0.334125$
$\Rightarrow 8x^3+27x^3+64x^3=0.334125$
$\Rightarrow 99x^3=0.334125$
$\Rightarrow x^3=0.334125\div99$
$\Rightarrow x^3=\frac{0.334125}{99}=0.003375$
$\Rightarrow x^3=\frac{3375}{1000000}$
$\Rightarrow x=\sqrt[3]{\frac{15\times15\times15}{10\times10\times10\times10\times10\times10}}=\frac{15}{10\times10\times10}=0.015$
Therefore, the numbers are:
$2x=2\times0.015=0.03$
$3x=3\times0.015=0.045$
$4x=4\times0.015=0.06$
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