A 6-sided dice has faces numbered 1,2,3,4,5 and 6 , when it is thrown the number facing up is the score , if it is thrown three times.
a) Find the probability that the total score is 18.
b) Find the probability that the score on the third throw is exactly the double of the score of the first two throws.
My turn :
The possibilities for a is just one possibility which is the three throws have the number 6 , then the answer is $$\frac{1}{216}$$
The possibilities for b are two , which are the third has the number 6 and the second and the first have 1 and 2 or 2 and 1
The the answer is $$\frac{2}{216}$$
Do these answers sound correct ?
Best Answer
You almost have it!
The first one is good.
For the second one, you missed the possibility that the two first dice show 1 and 1, and the third shows 4. So the probability is actually $\frac{3}{216}=\frac1{72}$.