bhg; CaC is right; I think you did your sum wrong. I worked it out your way and it came to 5.77%. CaC's method is simpler and gives the right answer of 5.77%
CAC: divide 22,000 by 20,800 and the bit after 1 is the increase percentage. that gives 1.0577 you need to subtract 1 and multiply by 100 but it does give the answer if you can pick it out.
I blame Mrs Sugg 1963 for laughing when I showed uncertainty about mark up and profit - -
ha ha ha she went instead of explaining it
and it was all due to Mrs S father wasnt a grocer and mine was ....