INTRODUCTION

A couple of aeons ago in the post I put up immediately before setting off for Marxism 2018 I presented two problems from brilliant.org, one easy and one hard. Now at long last I offer solutions to them.

THE GUARDS PROBLEM

Here is the answer:

Now here is an official solution, posted by Siva Budaraju:

Yes, Anna, you were right about this one, as you are about many things. 

THE CLOCK PROBLEM

For this one I shall present the confirmation that my answer was correct, my sneaky way of solving the problem and then an official solution.

I got the solution by realising that if there was an arrangement of the hands that enabled this to happen it would not be unique – as with problems involving two hands on a clockface there would be a number of possibilities, which would mean that finding such an arrangement would not be very difficult, and this was supposed to be a dificult problem, which led me to the conclusion that there could not be a time when the three hands divided the clockface into equal segments. Now here are two official solutions:

A NEW PROBLEM

I finish by sharing another problem with you that I enjoyed solving: