SOLUTION: A hat has 5 slips of paper numbered 1, 2, 3, 4, 5. A slip of paper is selected at random and its number noted and the slip is not replaced. A second slip of paper is selected a

Algebra ->  Probability-and-statistics -> SOLUTION: A hat has 5 slips of paper numbered 1, 2, 3, 4, 5. A slip of paper is selected at random and its number noted and the slip is not replaced. A second slip of paper is selected a      Log On


   

Question 1171202: A hat has 5 slips of paper numbered 1, 2, 3, 4, 5. A slip of paper is selected at
random and its number noted and the slip is not replaced. A second slip of paper
is selected at random.
What is the probability that the numbers selected sum to 6?

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
5 ways to choose the first and then 4 ways to choose the second.
That is 20 total ways
four of them add to 6: they are 1-5 and 5-1 and 2-4 and 4-2.
The answer is 20% or 1/5.
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if 1, (20% probability) then the other choices are 2-3-4-5 with equal probability of 25%.
So probability is 5% with each pairing and 1-5 sums to 6.
same for 2 and 2-4 with 5%
0 probability if first piece is 3.
the 5% probability with 4 and then 2
and with 5 and then 1.
Overall, it is a 20% probability.