Brenda set her watch 14 seconds behind, and it falls behind another 1 second every day. How far behind is Brenda's watch if she last set it 13 days ago?
So it's already 14 seconds behind, we know that, and every day it is +1 and we know that there has been 13 days so 13 times 1 is 13 plus the 14 seconds that were already behind so 13 plus 14 is 27, 27 seconds behind
