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}

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?

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 \(\displaystyle \binom{49}{7}\) possible combinations of seven B-numbers.
Of all those only 43 contain the six A-numbers.