This clock shows 6:40. What time will its mirror image show 35 minutes from now?

In 35 minutes the clock will show 7:15, and the mirror image of 7:15 is 11:60 - 7:15 = 4:45. The image runs backwards, so it is the present image 5:20 minus 35 minutes. (5:55 adds the 35 minutes to the image; 7:15 is the clock itself.)