those i couldn't do or even my friend, or even understand , if u r REAL expert DO THEM if u r not sure or normal teacher , please don't try and do not ask for further information , the questons are completes , it is matter of ur exprience and level, this is university grade , pay attention to decimel and provide explanaiton fully , we need explanation for those ASAP to prepare

Question 4 An optical system comprises in turn, from left to right: an observer, a lens of focal length +31 cm, an erect object 20 mm high, and a convex mirror of radius 80 cm. The object is between the lens and the mirror, 20 cm from the lens and 50 cm from the mirror. The observer views the image that is formed first by reflection and then by refraction. What is the position of the final image, measured from the mirror (in cm)? f R=80cm 20 mm Your Answer: ic * Answer (+ }Hide hint for Question 4 The answer should be with one decimal