A beam of light coverage to a point P. A lens is placed in the path of the convergent beam 12 cm from P. At what point does the beam converge if the lens is to be 20 cm ?

Question

$\begin{array}{1 1} \text{The image is at 6.5 cm to the right of the lens, when the beam coverage } \\ \text{The image is at 6.5 cm to the left to the lens, when the beam coverage } \\\text{The image is at 7.5 cm to the right of the lens, when the beam coverage } \\ \text{The image is at 7.5 cm to the left of the lens, when the beam coverage }\end{array} $