In a row of children, Deepak is 10th from the left and Ajay is 12th from the right. When they exchange their places, Deepak will be 16th from the left end. Which of the following will be the new position of Ajay from the right end ?

18

Total number of students = position of Ajay before interchange + position of Deepak after interchange 

                                     = 12 +  16  - 1 = 27

Position of Ajay after interchange from right end =  28 - 10  = 18