An experiment consists of rolling two fair dice and adding the dots on the two sides facing up. What is the probability that the sum of the dots is 7 or 11?
Well there is a total of 20 different outcomes and you can only get a sum of 7 four times and 11 once so in total 5 times out of 20 so that is 5 to the twentieth place beyond the decimal but you can round that up to 0.5%.
If you have fair dice there are 36 different outcomes.
The probability of the dots being a seven is: 6 out of 36
The probability of the dots being an 11 is: 2 out of 36
There are six number sevens and 36 outcomes making it 6:36; there are two number 11 making it 2:36.