If Tomorrow is Sunday, what will be the day after 30 days

How do we solve it ?

If tomorrow is sunday, today is saturday.

A week has 7 days " Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday ".

30 / 7 = 4 ( Remainder = 2)

So you can say that after multiples of 7 days, the day will repeat itself as saturday.

Hence after 28 days saturday will occur again.

So we calculate after the remainder (2) , the answer is Monday.

Simple Logic = And whatever the remainder obtained is, add that to the day.