Question 1163422: A man tossed two fair dice what is the conditional probability that the sum of the two
dice will be 7, given that [5]
(i) The sum is odd.
(ii) The sum is greater than 6.
(iii) The two dice had the same outcome.
Answer by ikleyn(52887) (Show Source):
You can put this solution on YOUR website! .
Part (i)
The sample space is the set of all pairs (a,b), where "a" and "b" are integer numbers from 1 to 6 inclusive,
representing possible outcomes tossing of two dice.
So, the sample space has 6*6 = 36 elements, and they all have the same probability of each.
Now let's calculate the number of events with the odd sum of outcomes.
2 elements have the sum 3 : (1,2) and (2,1).
4 elements have the sum 5 : (1,4), (2,3), (3,2) and (4,1).
6 elements have the sum 7 : (1,6), (2,5), (3,4), (4,3), (5,2) and (6,1)
4 elements have the sum 9 : (3,6), (4,5), (6,3) and (5,4)
2 elements have the sum 11: (5,6) and (6,5).
The total number of events with the odd sum is 2 + 4 + 6 + 4 + 2 = 18.
Of them, the number of events with the sum 7 is 6.
Therefore, the conditional probability under the problem's question is = = = . ANSWER
Part (ii). Do this part similarly.
Part (iii) is a good entertainment problem.
Its destination is to solve the problem MENTALLY and MOMENTARILY and to make a reader laughing.
The answer is: the probability is zero, since the number 7 is not the sum of two equal integer numbers.
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If you want to learn this subject and this class of problems BETTER, DEEPER and WIDER, look into the lesson
- Rolling a pair of fair dice
in this site. You will find there many other similar solved problems.
Also, you have this free of charge online textbook in ALGEBRA-II in this site
- ALGEBRA-II - YOUR ONLINE TEXTBOOK.
The referred lesson is the part of this online textbook under the topic "Solved problems on Probability".
Save the link to this textbook together with its description
Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson
into your archive and use when it is needed.
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