It is given that the commercial rate for 1967 was 42000
The rate in 2018 was 5 million that means 5000000.
The number of years is given by:

So the formula for the geometric progression is given by:

Substitute:

To get:
![\begin{gathered} 5000000=42000r^(50) \\ r^(50)=(2500)/(21) \\ r=\sqrt[50]{(2500)/(21)} \\ r=1.100308364 \\ r\approx1.10 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/xo0cw2evof5n3wlmy3bx0apet9vk3vyctu.png)
Hence the rate is approximately 1.10.