1. 1 - (224/225)^29 = 0.121 (3 d.p.)
The possibility of no one else having the same number as you is (224/225)^29, which is why you have to subtract this number from 1. This is because you are given 1 number out of 225, therefore the possibility of everyone else's numbers be 224/225. And as you are you 1 of the 30 people, there will be 29 other people who has the possibility to match with your number
2. Highly Likely
3. 1 - (224!/195! x 1/(225)^29)
The possibility of someone else having the same DNA profile as you is 224/225, then a second person having the same number is 223/225 and so on. This is why factorials must be used. And in order to find the possibility match between 30 people, you must take 29 (as you are one of the people of 30) from 224 to achieve 195. The possibility of one person's DNA match is 1/225 and is to the power of 29 as there are 29 other people (not including you)
4. It is more likely that two people share the same number as there are more possibilities between two people rather than one fixed person and another person.