Students line up in a queue in which Ashish stands fifteenth from the left and Sachin is seventh from the right. If they interchange their place, Sachin would be fifteenth from the right. How many students are there in the queue?

Options

A. 21
B. 22
C. 29
D. None of these

Explanation

To solve the problem step by step, we can follow the reasoning outlined in the video transcript.

### Step 1: Understand the positions of Ashish and Sachin
- Ashish is 15th from the left.
- Sachin is 7th from the right.

### Step 2: Set up the equation for total students
When they interchange their positions:
- After the interchange, Sachin becomes 15th from the left.
- We need to find out how many students are in the queue.

### Step 3: Define the total number of students
Let the total number of students in the queue be \( N \).

### Step 4: Use the positions to form an equation
From the given positions:
- The position of Ashish from the left is 15, which means there are \( N - 15 \) students to his right.
- The position of Sachin from the right is 7, which means there are \( N - 7 \) students to his left.

### Step 5: Analyze the interchange
After the interchange:
- Sachin is now 15th from the left, which means there are \( N - 15 \) students to his right.
- We know that after the interchange, Sachin is also 15th from the right.

### Step 6: Set up the equation for Sachin's new position
Since Sachin is now 15th from the right, we can write:
\[ N - 15 = 15 - 1 \]
This simplifies to:
\[ N - 15 = 14 \]

### Step 7: Solve for \( N \)
Now, solve for \( N \):
\[ N = 14 + 15 \]
\[ N = 29 \]

### Conclusion
Thus, the total number of students in the queue is **29**.

---