Question

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

Answer 1

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.