Two dice were thrown and it is known that the numbers which come up were different. Find the probability that the sum of the two numbers was 5.
Two die having 6 faces each when tossed simultaneously will have a total outcome of 62=36
Let P(A) be the probability of getting a sum equal to 5.
Let P(B) be the probability of getting 2 different numbers.
Probability of getting 2 different numbers
= 1 – probability of getting same numbers
= 1 – 1/6
=5/6
Let 
be the probability of getting a sum = 5 and two different numbers at the same time.
The sample space of 
Tip – By conditional probability, 
where 
is the probability of occurrence of the event A given that B has already occurred.
The probability that the sum = 5 given that two different numbers were thrown:
