Teachers 

Mr. Dutch, Mr. English, Mr. Painter, and Mr. Writer are all teachers at the same secondary school. Each teacher teaches two different subjects. Furthermore:

• three teachers teach Dutch language;
• there is only one math teacher;
• there are two teachers for chemistry;
• two teachers, Simon and Mr. English, teach history;
• Peter does not teach Dutch language;
• Steven is chemistry teacher;
• Mr. Dutch does not teach any course that is taught by Karl or Mr. Painter.

What is the full name of each teacher and which two subjects does each one teach?

Table for Two 

You are sitting with one opponent at an empty, round table. Taking turns, you should place one dollar on the table, in such a way that it touches none of the coins that are already on the table. The first player that is not able to place a dollar on the table has lost. By tossing a coin, it has been decided that you may start.

Which strategy will you follow to make sure you are guaranteed to win? 

Fun with Fuses

Assume that you have a number of long fuses, of which you only know that they burn for exactly one hour after you lighted them at one end. However, you do not know whether they burn with constant speed, so the first half of the fuse can be burnt in only ten minutes while the rest takes the other fifty minutes to burn completely. Also, assume that you have a lighter.

How can you measure exactly three quarters of an hour with these fuses? 

Handshakes

Joseph and his wife went to a party where four other married couples were present. Every person shook hands with everyone he or she was not acquainted with. When the handshaking was over, Joseph asked everyone, including his own wife, how many hands they shook. To his surprise, Joseph got nine different answers.

How many hands did Joseph’s wife shake?