To roll a sum of six ant then a sum of 10 on his next two turns are independent events, so the probabiliity of it is the product of the probability of the two separate events.
A) The probability of rolling a sum of six determined in this way:
1) Events that result in a sum of six points:
1 and 5,
2 and 4,
3 and 3,
4 and 2,
5 and 1
=> 5 ways of having a sum of six.
2) Total number of possibilities = 6*6 = 36
3) Probability = positive events / total number of events = 5/36
B) The probability of rolling a sum of 10 is determined in this way:
1) Events that result in a sum of 10 points
4+6,
5+5,
6+4
Number of positive events: 3.
2) Total number of events: 6*6 = 36
3) Probability = positive events / total events = 3/36 = 1/12
C) Combined probability = (5/36) * (1/12) = 5/432 = 0.01157
Answer: 5/432 = 0.01157