Scott was going to sell all of his stamp collection to buy a video game. after selling half of them he changed his mind. he bought 15 more. how many did he start with if he now has 40?

Three baby penguins and their father were sitting on an iceberg 0.50.50, point, 5 meters above the surface of the water. the father dove down 4.74.74, point, 7 meters from the iceberg into the water to catch dinner for his kids. what is the father penguin's position relative to the surface of the water?