Answer
The light was emitted $~~6.6\times 10^8~~$ years ago.
Work Step by Step
In part (f), we found that the distance between the galaxy and the Earth when the light was emitted is $~~6.6\times 10^8~ly$
We can find how long ago the light was emitted:
$\Delta t = \frac{6.6\times 10^8~ly}{c}$
$\Delta t = 6.6\times 10^8~years$
The light was emitted $~~6.6\times 10^8~~$ years ago.
