A class has 105 students, where boys comprise 40% and girls comprise 60%. Shivani ranks 30th from the top, and there are 20 girls ahead of her. Find the number of girls ranked behind her.

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?