Good morning,
I am a little bit confused by the exact details.
For me the question of what profit means in this context is important, is this after paying the business owner's salary or before?
It is also unclear to me if the £3k "profit" is before the £800 rent or after it, is the shop really making £3.8k profit per month before or £2.2k after the rent for the unused shop.
If the store owner is paying herself, say £25k pa and is still making a £36k annual profit then it is quite a different question to the £36k/ £26.4k annual "profit" being her "salary".
In the second case any significant loss of sales would seem to make the business unviable/hobby/vanity.
Many small businesses have odd views on profit; They don't count the owner's salary as a cost, one pub that I know the owners pay themselves around or less than minimum wage as it allows them to have a style for the pub that they want but could not have if they paid themselves "properly".
Bye
Ian