Problema Solution
suppose christmas is on friday this year, in how many years form now will it be on sunday if no leap years are involved?
Answer provided by our tutors
no leap years means 365 days between one Christmas and the next
365 prime factors to 5*73
7 is a prime number
so there are no common prime factors
365 % 7 = 1, so the day Christmas falls on every year will shift by 1 day
it will be 7 years before Christmas again falls on a Friday, ignoring leap years