All 105 students in a class are standing in a row facing north. Ravi is 49th from the right end while Shruti is 38th from the left end. How many people stand between Ravi and Shruti?

The correct option is 18.

Let us break down the problem step-by-step to find the number of students standing between Ravi and Shruti.

Step 1: Understand the given data
- Total number of students in the row = 105
- All students are facing North (Left to Right sequence).
- Shruti's position from the left end = 38th
- Ravi's position from the right end = 49th

Step 2: Check if there is an overlap between Ravi and Shruti
To check if their positions overlap, let us calculate the sum of their positions from opposite ends:

$\text{Sum of positions}=38+49=87$

Since the sum of their positions (87) is less than the total number of students (105), there is no overlap between Shruti and Ravi. Shruti is standing on the left side of Ravi.

Step 3: Calculate Shruti's position from the right end or Ravi's position from the left end
Let us find Ravi's position from the left end using the formula:
$\text{Position from left}=\text{Total students}-\text{Position from right}+1$

Substituting the values for Ravi:

$\text{Ravi's position from left}=105-49+1=57\text{th}$

Step 4: Find the number of people between Shruti and Ravi
Shruti is at 38th position from the left end, and Ravi is at 57th position from the left end.

The number of students standing strictly between them is calculated as:

$\text{Students between}=(\text{Ravi's position from left}-\text{Shruti's position from left})-1$

$\text{Students between}=(57-38)-1=19-1=18$

Alternatively, using the direct formula for non-overlapping cases:
$\text{Number of students between}=\text{Total students}-(\text{Shruti's position from left}+\text{Ravi's position from right})$

$\text{Number of students between}=105-(38+49)=105-87=18$

Thus, there are 18 people standing between Ravi and Shruti.