Members of group can't access directory in linux

I was trying to create two directories assignment and exam_papers containing assignment and question paper text files inside them respectively. After that, I created two users vipin , booma.Then added vipin to teacher group and booma to student group respectively.

Idea

The idea is I wanted to set permissions for assignment and exam_papers directory like only members of the teacher group can read write to the assignment and exam_paper directory and members of student and other users can only read the content of assignment directory

Here You can see that I removed all permissions from other users for exam_paper directory and gives only Read permission to other users for assignment directory.

Motive of this is, members of student group and other users can't access the exam_paper directory and can access assignment directory with only Read permission

Result

The result of all this is that even members of teacher group can't access both of these directories

Directories require executable access to enter/see contents. So if you wanted a group to have access privileges to a directory chmod -R 775 assignment/ should work.