For first reflection at convex lens
Real image is formed at 1m from the lens.
This image acts as an object for the plane mirror after reflection, it's image is formed at 1m behind the plane mirror at I′
The image at I′ is the virtual object for the convex lens.
So, μ = −3m for I′
f = +0.5m for I′
For second refraction at convex lens.
For v = \(\frac 35\) = 0.6 (towards left of lens).
So distance from mirror ⇒ 2 + 0.6 = 2.6m (real image)