Question 1082003
The first is 1/2
A 4 appears with 1/6 probability
tails and a 3 is (1/2)(1/6)=1/12, since they are independent.
a 2,4,5 are 3 of 6 possibilities so probability is 1/2
finally getting a 4 is (5/6)(5/6)(1/6)=25/216 probability, since they are independent.  What you don't want *2, multiplied by what you do want.