Step-by-Step Calculation

We can solve this by finding the position of one person from both ends of the row. Let's use the right end as our primary reference point.

1. 
   Determine Shamika's Position from the Right:
   

   Nikhil is 17th from the right. Shamika is 3rd to the right of Nikhil, which means she is 3 positions closer to the right end.

   
   Shamika's position from right = 17 - 3 = 14th
   


2. 
   Determine Ravi's Position from the Right:
   

   Ravi is 5th to the left of Shamika, which means he is 5 positions farther away from the right end.

   
   Ravi's position from right = 14 + 5 = 19th
   


3. 
   Calculate the Total Number of Children:
   

   We now know Ravi's position from both ends of the row:

   
   
   
   
   • 20th from the left (given in the problem)
   
   
   • 19th from the right (as calculated above)
   
   
   
   

   We can use the standard formula to find the total number of people in a row:

   
   Total = (Left Position + Right Position) - 1


Total = 20 + 19 - 1 = 38
   

Final Answer: The total number of children in the row is 38.