Answer
A double-paned window (two sheets of glass) will pass about 85 percent of the incident light.
Work Step by Step
We know that 92 percent of the incoming light is transmitted through the first pane. Then, 92 percent of that amount is transmitted through the second pane.
$$(0.92)(0.92) = 0.8464$$
We calculate that 84.6 percent is transmitted through both panes of glass.