Persistent Systems Software Development Engineer interview questions

-Logic coding question on pattern printing: 1 112 11123 1111234 11123 112 1 - Difference between list and tuple - SQL query to find the max of a column (when i wrote the query, he switched his mic off and after 1 min he suddenly left)

1 st question I got was based on aptitude.First question boils down to solving for three variables using 2 equations.Second question was to write a program to print no of occourances of all characters in a string.Third question was on 4 fundamentals of oops.fourth question was on operating systems.it asks whether we can run a program whose size is greater than size of RAM.and the last question was on software development life cycle.