Marshmallows

Three young blokes are away for the night on a stag do. Finding a hotel room for £30.00 for the night, each paying £10.00. Once in their room they find it very poorly set out and ask the manager for some kind of compensation, The manager sends £5.00 up to them with the porter. As they cannot find a way of splitting 5 between 3 they each decide to take £1.00 each making it only £9.00 each for the room for the night and they tip the porter the £2.00 that is left. so work it out! 3 x £9.00 = £27.00 then add the £2.00 tip for the porter. this should equal £29.00 so where’s the other £1.00?
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