Amazon Device Associate interview questions

that guy draw a X and said to me make it as 9 by adding only one line in it?

1. There is a pond and at the center of it grows a beautiful lotus flower. The size of the lotus keeps on growing double each day. If you look after twenty days, the lotus will have covered the entire pond. How much time will the lotus take to cover half of the pond? 2. How can you cut a round cake three times to make eight equal slices? 3. Asked few questions about testing methodologies. 4. Was told to write a test case to test the ATM machine, Mobile WiFi workflow. calculator functionalities. 5. Since i mentioned that I'm a pro in scripting, i was asked to write some programs. (Java)