To find the probability of the sum of three dice being 7, you can use the concept of combinations.
First, let's analyze the possible combinations that result in a sum of 7:
1. (1, 1, 5)
2. (1, 2, 4)
3. (1, 3, 3)
4. (1, 4, 2)
5. (1, 5, 1)
6. (2, 1, 4)
7. (2, 2, 3)
8. (2, 3, 2)
9. (2, 4, 1)
10. (3, 1, 3)
11. (3, 2, 2)
12. (3, 3, 1)
13. (4, 1, 2)
14. (4, 2, 1)
15. (5, 1, 1)
There are 15 different combinations that result in a sum of 7 when tossing three dice.
Now, let's calculate the probability. The total number of possible outcomes when tossing three dice is 6^3 = 216 (since each die has 6 possible outcomes). Therefore, the probability is:
P(sum of 7) = Number of favorable outcomes / Total number of outcomes
P(sum of 7) = 15 / 216
Simplifying this fraction gives the probability:
P(sum of 7) = 5 / 72
So, the probability of obtaining a sum of 7 when tossing three dice is 5/72.