
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
If a die is rolled, event \( A = \{1, 2, 3\} \) consists of rolling one of the faces 1, 2, or 3. Similarly, event \( B = \{1, 2, 4\} \) consists of rolling one of the faces 1, 2, or 4.

The die is rolled 10 times. It is known that event \( A \) occurred exactly 6 times.

a) Find the probability that under this condition, event \( B \) did not occur at all.

b) Find the expected value of the random variable \( X \), which represents the number of occurrences of event \( B \).

Present the answer in LaTex format: \boxed{Your answer}
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