What’s given in the problem  Vidya’s rank from the top: (7) Divya’s rank is (7) ranks ahead of Medha. Divya’s rank is (3) ranks behind Vidya. Sushma’s rank from the bottom: (4) Sushma’s rank is (32) ranks behind Medha.
How to solve
Calculate Medha’s rank from the top, then calculate Sushma’s rank from the top, and finally calculate the total number of students.
Step 1 . Calculate Divya’s rank from the top. Divya is (3) ranks behind Vidya, who is ranked 7th. Divya’s rank is (7+3=10).
Step 2 . Calculate Medha’s rank from the top. Divya is (7) ranks ahead of Medha. Medha’s rank is (10+7=17).
Step 3 . Calculate Sushma’s rank from the top. Sushma is (32) ranks behind Medha. Sushma’s rank is (17+32=49).
Step 4 . Calculate the total number of students. Sushma is 4th from the bottom and 49th from the top. Total number of students is (49+4-1=52).
Solution  The total number of students in the class is
(52).