A boy is standing in a room whose ceiling and two adjacent walls are mirrors. The number of images formed are [[1]].

The formula to calculate the number of images formed = $\frac{360°}{Angle between the mirrors}-1$

In the question it is given that the walls are adjacent to ceiling so, the angle between the two mirrors is $90°$. So the images formed is $\frac{360°}{90°}-1$= 3 images