If Tomorrow is Friday, what will be the day after 78 days

How do we solve it ?

If tomorrow is friday, today is thursday.

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

78 / 7 = 11 ( Remainder = 1)

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

Hence after 77 days thursday will occur again.

So we calculate after the remainder (1) , the answer is Friday.

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