Four whole number taken at random are multiplied together. The chance that the last digit of the product is 1, 3, 7, or 9 is ? By Editor No Comment Answer : A. 16/625
If the probability that A will live 15 year is 7/8 and that B will live 15 year is 9/10, then what is the probability that both will live after 15 year ? By Editor No Comment Answer : B. 63/80
