First, we have just released some new research showing that millions of people in the UK are now sleep deprived. If you want to discover if you need more sleep, we have created The Sleep Test. Hope you find it interesting.
Second, here is the puzzle. Please do NOT post your answer, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.
My friend has 4 pieces of jewelry – a ring, a necklace, a bracelet and a brooch. Given that she can wear any number of the objects when she goes out, how many combinations of her jewelry does she have to choose from?
I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.