To solve this problem, let's first represent the average age of the committee members both currently and 4 years ago.
Let the average age of the committee members currently be denoted by 'A'. Similarly, let the average age of the committee members 4 years ago be denoted by 'B'.
According to the given information, the average age of the committee members currently is the same as it was 4 years ago. Therefore, we can write:
A = B
Now, let's consider the total age of the committee members currently and 4 years ago.
The total age of the committee members currently is denoted by '10A' (since there are 10 members in total), and the total age of the committee members 4 years ago is denoted by '10B'.
Since an old member has been replaced by a young member, the total age of the committee members currently will be less than the total age 4 years ago.
Mathematically, we can represent this as:
10A < 10B
Dividing both sides of the inequality by 10, we get:
A < B
From the above equation, we can conclude that the average age of the committee members currently is less than the average age 4 years ago.
Now, to find how much younger the new member is, we need to find the difference between the average age currently and 4 years ago.
A - B = 0
Therefore, the new member is 0 years younger than the old member.
Since the correct answer is not provided in the options, it seems that there might be an error in the question or the options. Please double-check the given question and options for accuracy.