Pradeep correctly remembers that his mother's is before twenty third February but after ninteenth February, whereas his brother correctly remembers that their mother's birthday is not on or after twentysecond February. On which day in February is definitely their mother's birthday ?

Correct Answer: 20 or 21

According to Pradeep : 20,21 or 22...(1)According to his brother : not 22....(2)From (1)&(2), the birthday falls on February 20 or 21.