See the situatiion shown on figure Find the positiion of image as seen by observe `A`..

Explanation

(i) As seen by observer `A`.
`R = -10cm`
`u = -10cm`
So, `(n_(2))/(V) - (n_(1))/(u) = (n_(2) - n_(1))/(R)`
`(1)(v) = (1.5)/((-10)) = (1-1.5)/((-10))`
`v = -10cm` (at `O`)