$$
\Delta L_{A I}=\alpha_{A l} l_{A l} \Delta \theta_{A l} \cdots \cdots-(1)
$$
similarly,
\begin{aligned}
&\Delta l_{F e}=\alpha_{F e} L_{F e} \Delta \theta_{F e}---(2) \\
&\frac{\Delta L_{A l}}{\Delta L_{F e}}=\frac{\alpha_{A l} L_{A l} \Delta \theta_{A l}}{\alpha_{F e} L_{F e} \Delta \theta_{F e}} \\
&=\frac{23 \times 10^{-6}}{11 \times 10^{-6}} \times \frac{0.24 L_{F e} \times(60-0)}{L_{F e}(45-0)} . \\
&=\frac{23 \times 0.24 \times 60}{495}=\frac{23 \times 0.24 \times 4}{33} \\
&\frac{\Delta L_{A l}}{\Delta L_{F e}}=\frac{22.08}{11 \times 3} \\
&=\frac{2.0072}{3}=\frac{1}{3} \\
&=\frac{1}{1.49}=1: 1.49
\end{aligned}