We already know that one person has a birthday on blank day. We will call this person a. That means that there is a 100% chance that they have that birthday.
Because there are 365 days in a year, the odds of person b having a birthday on a certain day is 1/365
Odds of person A having that birthday: 365/365
Odds of person B having that birthday: 1/365
To find the odds of them having the same birthday, we must multiply these odds.
365/365 * 1/365 = 1/365
1/365 = 0.27%
This means that there is a 0.27% chance that both people share the same birthday.
To find the total price, we use this equation: 42 + 0.039(42) We can make it simpler: 1.039(42) Multiply: 43.638 Because we're rounding The total price is $43.64
