Question

A convex lens of focus distance 30 cm from a real image which is in a enlarged 3 times then the object find the object distance.

Answer 1

f=30cm v=3u
w.k.t 1/f=1/v_1/u
1/30=1/3u_1/_u
1/30=_u_3u/3u

u

Answer 2

Answer:

Explanation:

Please someone explain me the solution