You are given eight coins and told that one of them is counterfeit. The counterfeit one is slightly heavier than the other seven. Otherwise, the coins look identical. Using a simple balance scale, how can you determine which coin is counterfeit using the scale only twice?
First weigh three coins against three others. If the weights are equal, weigh the remaining two against each other. The heavier one is the counterfeit. If one of the groups of three is heavier, weigh two of those coins against each other. If one is heavier, it’s the counterfeit. If they’re equal weight, the third coin is the counterfeit.
They are the origins of the names of each day of the week.
Sunday – Sun day. Monday – Moon day. Tuesday – Tiw’s or Týr’s day, the god of single combat, son of Odin. Wednesday – Woden’s or Odin’s day, god of poetry and of the dead. Thursday – Thor’s day, god of thunder, son of Odin. Friday – Frigg’s day, goddess of the clouds, wife of Odin. Saturday – Saturn’s day, god of fertility and agriculture.
On the sixth of May in the year 1978 at exactly thirty-four minutes past noon, a most extraordinary event occurred. This singular occasion will probably never be witnessed by anyone who was alive at that time. What happened?
The time and date was 12:34 5/6/78, counting from one to eight. The next time this event will occur is 12:34 6 May 2078. Unless someone alive in 1978 lives to be over a hundred, they won’t be alive when it happens again.