Mensa Norway last 3 questions

I had no problems with solving first 32 questions from http://test.mensa.no but the last 3 questions are totally bugging me out even knowing the answers. Could anyone help me getting the logic behind them?

Answers are:

E A D

2 Answers

For the last one:

All the diagonals and broken diagonals have a shape in common. For those going NE we have:
And for those going SE we have:

For the second one:

The black balls follow the rule of diagonals going NE described above. The white balls follow a separate rule:

There are two white balls in every cell and they move in a counter-clockwise direction in the column they are in, as shown by the yellow balls above. If a white ball is at the same location as a black ball, only the black ball is shown.

The link provided by @Duck in the comments gives the answer to the first problem, so all three problems should now be answered.

• I saw this answer in comments but tbh I don't get the explanation for the first riddle. Could you explain it better for me? – Michał Pilarek Sep 19 '19 at 8:32
• Look at the $3$ NE diagonals and assume the triangles can flip across the line they are connected to. Only one flip is allowed per row change and you start in the top row, moving down. Assume also that a striped triangle flipped onto a white triangle gives a striped triangle. Hope that helps! – Jens Sep 20 '19 at 1:55
• Ok, now I get it – Michał Pilarek Sep 20 '19 at 11:26
• The answer could also be E for the last one since because each row has in total then (of the rectangle) two tops, one bottom and one left and one right. This is why iq tests often annoy me because you can have a logically consistent answer and still be wrong. Oh well they are for mainlynfor people who don't know that they are smart (which probably means they are not if they take it). – Deepthinker101 Sep 20 '19 at 23:13

Answer for the first Puzzle - The amount of triangles that are directed up & down should be balanced. 7 stripped triangles UP - 7 stripped triangles DOWN To make the balance for the blank one you need to choose an answer D.