two bags contains 10 balls each. Every round you choose with equal probability one of the two bags and pick out a ball. After a while, you choose an empty ball. What is the probability for the other bag to contain exactly 4 balls at that time？

6.10%

Step-by-step explanation:

For every round since we are choosing with equal probability, then the probability of choosing from either of the bags is 1/2

Here, this scenario is only possible when a particular bag has been chosen 10 times and the other bag has been chosen 6 times ( meaning a particular bag has been emptied and for a particular bag to be emptied, all of its content would have been picked)

Now on the 17th trial, an empty bag is chosen

Therefore the required probability will be;

16C0 * (1/2)^10 * (1/2)^6 * 1/2 = 0.0610 = 6.1%

for b its (t) and c its (d)

step-by-step explanation:

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!