Riddle of the week

This is a shout out to all you keen beans - can you crack the weekly riddle?

Any solutions win you major RSY-Netzer kudos and general 'win points'. If you collect a sufficient number of 'win points' you will become officially 'cool'. You can put that on your CV and everything...

Anyway, get solving!

Riddle 1 - The Royal mint a.k.a the Bendicks puzzle

You are the treasurer in charge of the Royal mint, which produces a single type coin, the grote. There are ten machines producing grotes, one machine is producing grotes weighing one gram less than they should, each coin should weigh 10 grams. You have aset of broken scales which can be fixed to provide one single weigh of a single amount (no weight changes are allowed). Using the scales once you must identify the single faulty machine.

Riddle 2

There are 3 RSY-Netzernikim being held captive. They all have perfect powers of deduction. They are blindfolded and placed in a line facing in the same direction, such that the person at the back can see the two in front, the person at the front can see nobody, and the girl in the middle can only see the person at the front. They have a hat placed on their head (still blindfolded) and are told that these hats have been chosen from a box with 3 black hats and 2 white hats. They are told that they can all go free if and only if one of them guesses the correct colour hat that they are wearing. They may not speak to one another or touch one another, turn around or cheat in any way (and they cannot see the box from which the hats have been taken). Their blindfolds are then removed and after a short pause, one of them gets it right and they are freed. Explain how this happens. 

Riddle 3

Using ALL of the numbers 1, 3, 4 and 6 only once make the number 24, using only the symbols + - x ÷ ( ) ^ =

Riddle 4

Riddle 5