There are 28 individuals in a room. Each person will celebrate their birthday in 2016 on the Sunday of the week concluding their birth. Nobody is born on February 29. What is the probability that 2 parties happen in 2016 on the same day.
Note: I asked my lecture to clarify and he said anybody in the last week of December will have their birthday in 2017. This makes the problem so confusing to me.
I thought it might be best to approach it from an inclusion-exclusion perspective? Or could I simply subtract from 1 the probability that nobody shares a birthday? How do I count this? There are 52 Sunday's in 2016, the Sunday after feb 29th only has 5 days preceding it, so will I have to count this one differently as well?