A Limey sent me this:

Three business men walk into a hotel. The price for a single room is £100, so they each pay the hotel receptionist £100, and go off to their rooms.

The hotel manager then comes down. He says, "We've got a special offer at the moment: if three business people arrive together, they can have their rooms for a total of £250. Take £50 from the till, and go and give it back to them." The receptionist is cunning, however, and he thinks: "dividing £50 between three people won't be easy. Why don't I take five £10 notes from the till, give each of the businessmen £10 each, and keep the rest myself?".

So now, having paid £100 each and received £10 back, each businessman has paid £90 for his room. And having given back £10 to each of the three businessmen, the receptionist still has £20 of the £50 he over-charged them. But three times £90 is £270, which with the receptionist's £20 makes £290.

So what's become of the remaining £10?

Well?

Subtract the £20 instead of adding it and you have the £250, which is the number the problem actually calls for.

Thank you for asking. I got to learn how to type '£' on a US-centric laptop.

Yes original charge was for 300 and reduced to 250. Fifty refunded and 10 given to each of three guests. This comes to 270 minus the 20 kept by the receptionist. Reducing money paid to hotel to 250.

Solving for the 250 paid to the hotel and not the 300 originally collected.

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daifu-orchid (imported) wrote: Sun Dec 29, 2013 7:22 pm But three times £90 is £270, which with the receptionist's £20 makes £290.

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You only multiply those numbers if you want to cheat someone out of £10.

This is one of the examples you use when teaching the rules of addition., subtraction, multiplication and division.