Ravi is 7 ranks ahead of Sumit in a class of 39. If Sumit's rank is seventeenth from the last, what is Ravi's rank from the start?

A certain number of students are standing in a row. Rishabh stands 40th from the left. Mahak stands 42nd from the right. Mahak is standing to the right of Rishabh. If there are only 5 students between Rishabh and Mahak, how many students are standing in the row?

Mahesh ranked 21st from the top and 15th from the bottom in his class. How many students are there in the class?