Final answer:
The composite number that satisfies the given condition is 20.
Step-by-step explanation:
The question states that the number is composite, greater than 16 and less than 22.
We can start by listing the composite numbers between 16 and 22, which are 18, 20, and 21.
Now, let's analyze the condition that 'of my digits are a number and the number doubled'.
Starting with 18, its digits are 1 and 8. If we double 1, we get 2, which is not the other digit.
Therefore, 18 does not satisfy the condition.
Next, let's check 20. Doubling 2 gives us 4, which is the other digit. So, 20 satisfies the condition.
Finally, let's check 21. Doubling 2 gives us 4, which is not the other digit.
Therefore, 21 does not satisfy the condition.
Based on our analysis, the number that satisfies the condition is 20, option b).