21. An unbiased die with faces marked 1, 2, 3, 4, 5 & 6 is rolled four times. Out of four face values obtained the probability that the minimum face value is not less that 2 and the maximum face value is not greater than 5, is :
(a) 16/81 (b) 1/81 (c) 80/81 (d) 65/81
Answer : (a)
Explanation : No answer description available for this question. Let us discuss.
Probability » Exercise - 115. The probability of happening atleast one of the events A & B is 0.6. If the events A & B happens simultaneously with the probability 0.2, then (a) 0.4 (b) 0.8 (c) 1.2 (d) none of these