Select a counter-example that makes the conclusion false.

you select three marbles from a bag and each of them is black.

conclusion: all the marbles in the bag are black.

counterexample:

You select three marbles from a bag and at least one of them is not black.

Step-by-step explanation:

We are given a statement,

' You select three marbles from a bag and each of them is black. '

It is required to write a counter-example for the conclusion of this statement.

Now, counter-example is used to oppose or contradict an idea or a theory.

As, we have the conclusion,

' All the marbles in the bag are black. '

It's contradiction will be that not all marbles in the bag are black. Since, we do not know how many marbles are there in the bag.

Hence, the counter-example of the conclusion is 'You select three marbles from a bag and at least one of them is not black'.

4x and 6y

im not sure though