Answer
\[\underline{\text{0}\text{.28 lb/i}{{n}^{3}}}\]
Work Step by Step
The relationship between pound and g is as follows:
\[\begin{align}
& 1\text{ lb}=\text{453}\text{.59237 g} \\
& \text{1 i}{{\text{n}}^{3}}=16.387\text{ c}{{\text{m}}^{3}} \\
& 1\text{ lb/i}{{n}^{3}}=27.68\text{ g/c}{{\text{m}}^{3}}
\end{align}\]
So, density in pounds per cubic inch will be as follows:
\[\begin{align}
& \text{1 g/c}{{\text{m}}^{3}}=\left( \text{1 g/c}{{\text{m}}^{\text{3}}} \right)\left( \frac{\text{1 lb/i}{{\text{n}}^{\text{3}}}}{\text{27}\text{.68 g/c}{{\text{m}}^{\text{3}}}} \right) \\
& =\text{0}\text{.036 lb/i}{{\text{n}}^{\text{3}}} \\
& \text{7}\text{.68 g/c}{{\text{m}}^{\text{3}}}=\left( \text{7}\text{.86 g/c}{{\text{m}}^{\text{3}}} \right)\left( \frac{\text{0}\text{.036 lb/i}{{\text{n}}^{\text{3}}}}{\text{1 g/c}{{\text{m}}^{\text{3}}}} \right) \\
& =\text{ 0}\text{.28 lb/i}{{\text{n}}^{\text{3}}}
\end{align}\]
Density of iron in pounds per cubic inch is \[\underline{\text{0}\text{.28 lb/i}{{n}^{3}}}\].
