Conquer Club

Dear fellows, too lazy to make calculations for those values listed below, and i urgently need if any of you have a link for if any previous work had been handled on this....

1/ What is the probability of red/blue/green set in 3 cards ?
2/ What is the probability of mixed set in 3 cards ?
3/ What is the probability to have any set in 4 cards ?
4/ What is the probability to be 2 pairs ?

This is urgent and will highly be apprecited if any of you could provide me a link to previous and reliable works handled before....

Thanks,
H.A.

By my calculations:

1. 1/9 (3 r/g/b sets, 27 possibilities)
2. 2/9 (6 mixed sets, 27 possibilities)
3. 7/9 (1/3 chance to get a set in 3 cards, then a 2/3 chance to get a set when you draw your 4th card)
4. 2/9 (The opposite of #3)

Thanks for the answer