# What is probability?

• May 13th 2010, 10:50 AM
aRTx
What is probability?
If someone picks 6 numbers first from A={1,2,3,...,46,47,48,49} remeber these numbers and put these back.

Then if he picks 7 numbers from A={1,2,3,...,46,47,48,49} what is the probability to take the first six numbers?
• May 13th 2010, 04:31 PM
matheagle
what does this

Quote:

to take the first six numbers?
mean?

and are you sampling with or without replacement each time?
• May 15th 2010, 09:06 AM
aRTx
To be more precisly, Look if there are two Set with balls
A:{1,2,3,...,47,48,49}
B:{1,2,3,...,47,48,49}

http://comps.fotosearch.com/comp/FSA...~x15158860.jpghttp://comps.fotosearch.com/comp/FSA...~x15158860.jpg
If you take six balls from one of them and after that you take seven balls from another. What is probability to have the six numbers from set A, same with six of seven from set B?
• May 15th 2010, 09:24 AM
Plato
Is the correct? Once we have a set of six numbers from batch A, then we randomly select seven numbers from batch B.
Question: what is the probability that the six A-numbers are among the seven B-numbers?
If that is correct then note that there are $\binom{49}{7}$ possible combinations of seven B-numbers.
Of all those only 43 contain the six A-numbers.
• May 16th 2010, 09:45 AM
aRTx
Yes it is correct!

Can you tell me the probability pls...?