Junior Trader Interview Questions

5/11 let's say d is the probability that 10 or 11 comes up before 7. probability of rolling 10: (6+4,4+6,5+5) = 3/36 probability of rolling 11: (6+5,5+6): 2/36 probability of rolling 7: (6+1,1+6,5+2,2+5,4+3,3+4): 6/36 d = you roll 10 or you roll 11 or (you roll something other than 10,11,7 and roll 10 or 11 before 7) d = (3/36) + (2/36) + (25/36)*d (11/36)*d = (5/36) d= 5/11

Anonbyfar is correct, 5/11 is the right answer but for the wrong question

doesnt the answer by 'Anonbyfar' (17/132) give you the probability of rolling a 10 and 11 within two rolls? Shouldnt this be then related to the probability of rolling a 7 (6/11). I.e 17/72?

P(10 or 11 before 7) = P(10 or 11 | 10 or 11 or 7) = [P(10) + P(11)]/[P(10)+P(11)+P(7)] P(10) = 3/36 4,6 5,5 6,4 P(11)= 2/36 5,6 6,5 P(7) = 6/36 1,6 2,5, 3,4 4,3 5,2 6,1 Answer: 5/11

roll 10 or 11: 5 cases roll 7: 6 cases roll others: 25 in total: 36 cases So Pr = 5/36 + 25/36 *Pr Pr = 5/11