There were 156 students in a room. 81 students left the room and some students entered the room. There were 108 students in the room in the end. How many students entered the room
33 students entered the room.
Initially, there were 156 students in the room.
After 81 students left, there were 156 - 81 = 75 students remaining.
Let x be the number of students that entered the room.
So, the total number of students in the room after some students entered is 75 + x.
Given that in the end, there were 108 students in the room.
Therefore, 75 + x = 108
x = 108 - 75
x = 33
Therefore, 33 students entered the room.