How to cut out set interval?

I am working on a large audio file and I added in large amount of silence between the tracks, now I want to go back and remove some of those long pauses and trim them down. How may I clip let’s say exactly 3 seconds from each file? Doing this manually with the mouse is not accurate enough. Is there a easy way to do this?

Zoom in so that you can precisely click at the place where you want to start the deletion.
Set the duration that you want to delete in the Selection Toolbar.
Then press the Del key.