Consider a concave mirror and a convex lens (refractive index = 1.5) of focal length 10 cm each, separated by a distance of 50 cm in air (refractive index = 1) as shown in the figure. An object is placed at a distance of 15 cm from the mirror. Its erect image formed by this combination has magnification $$M_1$$. When the set-up is kept in a medium of refractive index $$\frac{7}{6}$$, the magnification becomes $$M_2$$. The magnitude $$\mid \frac{M_2}{M_1} \mid$$ is