We use the mirror formula: $\frac{1}{v} + \frac{1}{u} = \frac{1}{f}$.

Case 1 (Initial Position): Object distance, $u_1 = -40 \text{ cm}$. Focal length, $f = -15 \text{ cm}$ (concave mirror). $\frac{1}{v_1} = \frac{1}{f} - \frac{1}{u_1} = \frac{1}{-15} - \frac{1}{-40} = \frac{-8 + 3}{120} = \frac{-5}{120}$. $v_1 = -24 \text{ cm}$. The initial image is 24 cm in front of the mirror.

Case 2 (Final Position):

• The object is displaced 20 cm towards the mirror. New object distance $u_2 = -(40 - 20) = -20 \text{ cm}$. $\frac{1}{v_2} = \frac{1}{f} - \frac{1}{u_2} = \frac{1}{-15} - \frac{1}{-20} = \frac{-4 + 3}{60} = \frac{-1}{60}$. $v_2 = -60 \text{ cm}$. The new image is 60 cm in front of the mirror.

Displacement: Displacement = $|v_2| - |v_1| = 60 - 24 = 36 \text{ cm}$. Since the image distance increased from 24 cm to 60 cm, the image moved away from the mirror.

Thus, the displacement is 36 cm away from the mirror.