In part b of the question it is written remove results of subsidiary and gain on disposal and prepare a revised statement of p and l. In the workings of answer they have added the gain in operating expenses , shouldn’t gain be deducted.
The gain that was originally included in the operating expenses should not have been, and hence they are reversing it out. It would have reduced the operating expenses initially but to remove it we will need to add it back to get back to the original expense figures.