Answer

The answer to the puzzle:

Each person pays £9, so in total they paid 3 x £9 = £27.

This covers the cost of the meals (£25) and the waiter’s tip (£2).

Adding the tip is wrong, as it is already included. You are adding it twice. You should really include the three £1 returns to the customers:

3 x £9 = £27

3 x £1 = £3

£27 + £3 = £30, as required.

Puzzle

I used to love giving people simple puzzles, so here is one for you:

Three people go into a restaurant.

They each eat and the total bill is £30, so they pay £10 each (3 x 10 = 30) and leave.

After leaving, the manager realises he has charged them £5 too much, so sends the waiter after them.

The waiter realises splitting £5 between three is tricky, and besides, he got no tip, so he keeps £2 and gives each person £1 back.

That means each person paid £9.

3 x £9 = £27

Add the waiter’s tip: £27 + £2 = £29

So, where has the other pound gone?

Answer in a couple of days…