Answer: 17/19
Explanation:
Number of red rocks = 6
Number of orange rock = 1
Number of blue rocks = 4
Number of white rock = 1
Number of yellow rocks = 7
Total number of rocks = 19
Probability of not getting a orange the first time will be (1 - 1/19) = 18/19.
Probability of not getting an orange the second time will be: (1 - 1/18) = 17/18
Probability of not getting an orange on both occasion will be:
= 18/19 × 17/18
= 17/19