Margaret will toss a sum of 6, if one of the following situations occurs:
1. The first cube is 1 , the second cube is 5 : sum 6.
2. The first cube is 2, the second cube is 4: sum 6.
3. The first cube is 3, the second cube is 3: sum 6.
4. The first cube is 4, the second cube is 2 : sum 6.
5. The first cube is 5, the second cube is 1 : sum 6.
So, there are 5 possible situation that suit for Margaret.
The probability that Margaret will win is:
number of "good" situation/ number of all possible situations .
There are 24 possible situations, so the probability is: 5/24