need help with probability (1 Viewer)

[koizora]

1) in the lottery game, three numbers are selected from 1,2,3,4,....40. find the probability that the three selected numbers are all even

2) if every possible order of finishing is equally likely in the race with nine constestants, find the probability of picking the first three placegetters in their correct order

3) Three cards are drawn at random from a pack of 52 playing cards. what is the probability that they are all from the same suit

thnk you​

 

[Pwnage101]

1) note it is WITHOUT repalcement ---> 20/40 * 19/39 * 18/38
2)1/9 * 1/8 * 1/7 ---> not sure bout thisone
3)13/52 * 12/51 * 11/50 * 4

somebody confirm please

 

[FFC]

1) note it is WITHOUT repalcement ---> 20/40 * 19/39 * 18/38
2)1/9 * 1/8 * 1/7 ---> not sure bout thisone
3)13/52 * 12/51 * 11/50 * 4

somebody confirm please

1. Looks right,

2. Again, looks right - there is only one correct choice, but there are 9*8*7 possible outcomes, therefore 1/504

3. I'm pretty sure this is wrong. Reading the question, I get the impression that the first choice of card is unimportant. You could choose any card and it would be ok - it's choosing the same suit for the NEXT two cards that is important.

So, P(all same suit) = 1 * (12/51) * (11/50) = 22/425