Vikas is 21st from the right end in a row of 40 boys. What is his position from the left end?

In a row of 39 people facing north, Lavanya sits 17th from the left end. If Rajat sits 5th to the right of Lavanya, what is Rajat's position from the right end of the line?

In a row of 50 students facing north, Hari is 10th from the right end. If Kapil is 4th to the left of Hari, what is Kapil's position from the left end of the line?