Question
An unbiased coin is tossed. If the result is a head, a pair of unbiased dice is rolled and the number obtained by adding the number on the two faces is noted. If the result is a tail. a card from a well shufled pack of eleven cards numbered 2,3,4,...,12 is picked and the number on the card is noted. The probability that the noted number is either 7 or 8, is k729, then the last digit of k is