To calculate the probability that at least two of the three babies were born on the same day, you can use the complement rule, which states that the probability of an event occurring is equal to 1 minus the probability of the event not occurring.
Let's calculate the probability that none of the babies were born on the same day:
1. For the first baby, there are 7 days of the week to choose from.
2. For the second baby, since we want none of them to share a birthday, there are 6 remaining days to choose from.
3. For the third baby, again, there are 6 remaining days to choose from.
So, the probability that none of them were born on the same day is:
(7/7) * (6/7) * (6/7) = 252/343
Now, to find the probability that at least two of them were born on the same day, we use the complement rule:
Probability(at least two born on the same day) = 1 - Probability(none born on the same day)
Probability(at least two born on the same day) = 1 - 252/343 = (343 - 252)/343 = 91/343
So, the probability that at least two of the three babies were born on the same day is 91/343.