Sunita's birthday was on 15 March 2020 which was a Sunday. If her husband's birthday was one 31 May 2020. On which day would it fall ?

Sunday

Sunita's birthday was on 15 March 2020 which was a Sunday.

If her husband's birthday was one 31 May 2020 the day will be?

Note, a day repeats itself after every seven days.

So the number of days between 15 March 2020 to 31 May 2020 = 77

If we divide 77 by 7 we get 0 as remainder it means the day will be same as on 31 may 2020. I.e sunday.