The Sufferfest enters another dimension with 4D Power

power 4dWin a 4D lottery winning numbers has never been easier and is not based on luck. It's all about math, manipulation, statistic and hardworking study on how to win. Our 4D prediction6. A convex lens of power +6 D is placed in contact with a concave lens of power –4D. What will be the nature and focal length of this combination ? (a) convex, 100 cm (b) convex, 50 cm