You are chatting with two of your friends and mention that you were born on a Sunday. What is the chance that at least one of these friends was also born on a Sunday?

1/7 because yenno there's 7 days in a week & only 1 Sunday

2/7

Step-by-step explanation:

This is a very simple question worded very weirdly.

There are seven days in a week and only one Sunday in a week.

So the chance that one friend was born on the same week of the day is 1/7.

However, there are 2 friends and we are looking for the probability that at least one of these friends was also born on a Sunday, so we just add 1/7 + 1/7.

1/7 + 1/7 = 2/7, so the chance that at least one of the friends was also born on a Sunday is 2/7.