Hoodleehoo
New member
- Joined
- Dec 5, 2016
- Messages
- 12
Can someone explain this to me? I'm studying for the GRE and am stuck on this concept.
"If you roll a dice three times, what is the probability of rolling a 6 at least once?"
The correct answer is 91/216
I can figure it out by calculating the chance of not rolling any 6's and then subtracting it from 1,but I can't figure out how to calculate it directly.
I tried 1/6 + 1/6 + 1/6 but that = 1/2. What am I missing?? I thought I understood the concept, but obviously I don't. The book says for "or" questions to use addition (assuming mutually exclusive). This one really tripped me up.
Thanks so much in advance!!
"If you roll a dice three times, what is the probability of rolling a 6 at least once?"
The correct answer is 91/216
I can figure it out by calculating the chance of not rolling any 6's and then subtracting it from 1,but I can't figure out how to calculate it directly.
I tried 1/6 + 1/6 + 1/6 but that = 1/2. What am I missing?? I thought I understood the concept, but obviously I don't. The book says for "or" questions to use addition (assuming mutually exclusive). This one really tripped me up.
Thanks so much in advance!!